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Renal denervation (RDN) has been used for treating resistant hypertension. A few recent studies have shown vagal innervation of kidneys causing confusion. This study aimed to provide anatomical and functional evidence for renal autonomic innervation. Experiments were performed in male Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR). Pseudorabies virus (PRV) in the paraventricular nucleus and rostral ventrolateral medulla was prevented by bilateral RDN, but not subdiaphragmatic vagotomy. PRV did not appear in the dorsal motor nucleus of the vagus and nucleus tractus solitarii 72 h after renal injection of PRV. Adrenergic fibers were approximately seven times more than cholinergic fibers in the main renal artery (MRA) and its first (1RA) and second grade (2RA) branches. Adrenergic fibers in 1RA were more than those in MRA and 2RA. Tyrosine hydroxylase immunoreactivity in these arteries was higher in SHR than in WKY. Norepinephrine (NE) increased and α-receptor antagonist reduced vascular ring tension of renal arteries. The effect of NE was greater in 1RA and 2RA than in MRA, which was prevented by α-receptor antagonist. Acetylcholine (ACh) or blockage of β-receptors, M receptors, or N receptors had no significant effects on vascular ring tension and the effect of NE. Renal blood flow was reduced by electrical stimulation of renal nerves but not affected by stimulation of the subdiaphragmatic vagus. These results provide anatomical and functional evidence that kidneys are innervated and renal blood flow is regulated by renal sympathetic nerves rather than the vagus. Renal vasoconstriction is regulated by NE and adrenergic fibers rather than ACh or cholinergic fibers in WKY and SHR. NEW & NOTEWORTHY Kidneys are innervated by renal nerves rather than the vagus. Adrenergic fibers in renal arteries are about seven times more than cholinergic fibers. Renal vasoconstriction is regulated by norepinephrine and adrenergic fibers rather than acetylcholine or cholinergic fibers. Renal blood flow is regulated by renal sympathetic nerves and is not affected by the vagus. These findings provide anatomical and functional evidence for renal autonomic innervation in normotensive and hypertensive rats.

Increased sympathetic nerve excitability has been reported to aggravate a variety of chronic pain conditions, and an increase in the number of sympathetic nerve fibers in the dorsal root ganglion (DRG) has been found in neuropathic pain (NP) models. However, the mechanism of the neurotransmitter norepinephrine (NE) released by sympathetic nerve fiber endings on the excitability of DRG neurons is still controversial, and the adrenergic receptor subtypes involved in this biological process are also controversial. In our study, we have two objectives: (1) To determine the effect of the neurotransmitter NE on the excitability of different neurons in DRG; (2) To determine which adrenergic receptors are involved in the excitability of DRG neurons by NE released by sprouting sympathetic fibers. In this experiment, a unique field potential recording method of spinal cord dorsal horn was innovatively adopted, which can be used for electrophysiological study in vivo. The results showed that： Forty days after SNI, patch clamp and field potential recording methods confirmed that NE enhanced the excitability of ipsilateral DRG large neurons, and then our in vivo electrophysiological results showed that the α 2 receptor blocker Yohimbine could block the excitatory effect of NE on A-fiber and the inhibitory effect on C-fiber, while the α 2A -adrenergic receptor agonist guanfacine (100 μM) had the same biological effect as NE. Finally, we concluded that NE from sympathetic fiber endings is involved in the regulation of pain signaling by acting on α 2A -adrenergic receptors in DRG., Competing Interests: Declaration of competing interest There is no conflict of interest or financial interests, direct or indirect, that exist or may be perceived to exist for individual contributors in connection with the content of this paper., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Adrenergic innervation in the tissue of the cervical, mesenteric, and popliteal lymph nodes in rats of different age groups (from 2-45 days to 24 months) was studied using the specific fluorescence-microscopic imaging of catecholamines. Adrenergic innervation in the lymph nodes of rats is present from the first days of life, but it develops and complicates during postnatal ontogeny and is fully formed by thedays 20-30 of life. By the age of one month, adrenergic innervation represents a well-formed apparatus in all parts of the node, i.e. in the capsule, trabeculae, and cortical and medullary substance. These are brightly fluorescent nerve fibers that form plexuses with regularly located multiple varicosities. In senile animals, the density and number of plexuses in all parts of the lymph node are preserved, but the brightness of plexuses decreases, plexus fibers become discontinuous, varicosities become less frequent or disappear. These changes are seen in lymph nodes from different body regions.

Background: Brown adipose tissue (BAT) is present in humans and rodents, and contributes to energy expenditure by converting energy stored in lipids and glucose into heat. Beta adrenergic receptor (β-AR) agonists have been proposed as pharmacological tools to activate BAT, but they lack selectivity for this tissue. This study aimed to investigate the possibility to apply electrical neurostimulation as a novel approach to activate BAT by promoting the sympathetic outflow towards BAT., Methods: Male C57BL/6J mice were treated with either unilateral electrical neurostimulation of interscapular BAT or with the β3-AR agonist CL316,243. Thermogenesis, nutrient uptake by BAT and downstream signaling of adrenergic receptors in BAT were examined., Results: Electrical neurostimulation and β3-AR agonism acutely increased heat production by BAT, as evidenced by an increase in local temperature in BAT, without influencing the core body temperature. Both treatments acutely increased tyrosine hydroxylase content in the nerve terminals thereby confirming enhanced sympathetic activity. In addition, we identified increased phosphorylation of hormone-sensitive lipase coinciding with reduced intracellular lipids in BAT, without affecting acute nutrient uptake from plasma. The increased BAT temperature as induced by electrical neurostimulation was reversed by β3-AR antagonism., Conclusion: Electrical neurostimulation acutely promotes thermogenesis in BAT as dependent on β3-AR signaling. We anticipate that electrical neurostimulation may be further developed as a novel strategy to activate BAT and thereby combat (cardio)metabolic diseases., (Copyright © 2020 Li, de Jonge, Wang, Rensen and Kooijman.)

Hematopoiesis produce every day billions of blood cells and takes place in the bone marrow (BM) by the proliferation and differentiation of hematopoietic stem cells (HSC). HSC are found mainly adjacent to the BM vascular sinusoids where endothelial cells and mesenchimal stromal cells promote HSC maintenance by producing a variety of factors. Other cell types that regulate HSC niches include sympathetic nerves, non-myelinating Schwann cells and a variety of mature hematopoietic cells such as macrophages, neutrophils, and megakaryocytes. This review will focus on the role of adrenergic signals, i.e. of catecholamines, in the regulation of the HSC niche. The available evidence is rather controversial possibly due to the fact that adrenergic receptors are expressed by many cellular components of the niche and also by the often neglected observation that catecholamines may be produced and released also by the BM cells themselves. In addition one has to consider that, physiologically, the sympathetic nervous system (SNS) activity follows a circadian rhythmicity as driven by the suprachiasmatic nucleus (SCN) of the hypothalamus but may be also activated by cognitive and non-cognitive environmental stimuli. The adrenergic modulation of hematopoiesis holds a considerable potential for pharmacological therapeutic approaches in a variety of hematopoietic disorders and for HSC transplantation however the complexity of the system demands further studies. Graphical Abstract Sympathetic nerve termini may release NE while mature BM cells may release norepinephrine (NE) and / or epinephrine (E). Both may bind to β-adrenergic receptor (AR) expressed in nestin+MSC in the hematopoietic stem cell (HSC) niche and regulate the physiological trafficking of HSC by modulating the expression of CXCL12 and SCF. Both NE and E may also activate Lin - c-Kit+ Sca-1+ (LKS) cell via another AR. In addition, NE may also signal to α1-AR expressed in pre-B cells which by TGF-β secretion might regulate proliferation of their lymphoid progenitors in an autocrine manner and/or inhibit myeloid progenitors.

Blood pressure is a highly controlled cardiovascular parameter that normally guarantees an adequate blood supply to all body tissues. This parameter is mainly regulated by peripheral vascular resistance and is maintained by local mediators (i.e., autacoids), and by the nervous and endocrine systems. Regarding the nervous system, blood pressure can be modulated at the central level by regulating the autonomic output. However, at peripheral level, there exists a modulation by activation of prejunctional monoaminergic receptors in autonomic- or sensory-perivascular fibers. These modulatory mechanisms on resistance blood vessels exert an effect on the release of neuroactive substances from the autonomic or sensory fibers that modify blood pressure. Certainly, resistance blood vessels are innervated by perivascular: (i) autonomic sympathetic fibers (producing vasoconstriction mainly by noradrenaline release); and (ii) peptidergic sensory fibers [producing vasodilatation mainly by calcitonin gene-related peptide (CGRP) release]. In the last years, by using pithed rats, several monoaminergic mechanisms for controlling both the sympathetic and sensory perivascular outflows have been elucidated. Additionally, several studies have shown the functions of many monoaminergic auto-receptors and hetero-receptors expressed on perivascular fibers that modulate neurotransmitter release. On this basis, the present review: (i) summarizes the modulation of the peripheral vascular tone by adrenergic, serotoninergic, dopaminergic, and histaminergic receptors on perivascular autonomic (sympathetic) and sensory fibers, and (ii) highlights that these monoaminergic receptors are potential therapeutic targets for the development of novel medications to treat cardiovascular diseases (with some of them explored in clinical trials or already in clinical use)., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Introduction: In arthritic mice, a sympathetic influence is proinflammatory from the time point of immunization until the onset of disease (days 0-32), but reasons are unknown. Disruption of the major anti-inflammatory pathway through Gαs-coupled receptors probably play a role. For example, noradrenaline cannot operate via anti-inflammatory β2-adrenoceptors but through proinflammatory α1/2-ad-renoceptors. This might happen, first, through a loss of sympathetic nerve fibers in inflamed tissue with low neurotransmitter levels (noradrenaline only binds to high-affinity α-adrenoceptors) and, second, through an alteration in G-protein receptor coupling with a predominance of α-adrenergic signaling. We hypothesized that both mechanisms play a role in the course of collagen type II-induced arthritis (CIA) in the spleen in mice., Methods: In CIA mice, nerve fiber density in the spleen was quantified by immunohistochemistry techniques. The functional impact of sympathetic nerve fibers in the spleen was studied by a micro-superfusion technique of spleen slices with a focus on the secretion of IFN-γ and IL-6 (proinflammatory) and TGF-β (anti-inflammatory)., Results: During CIA, sympathetic nerve fibers get increasingly lost from day14 until day 55 after immunization. The influence of electrically released noradrenaline diminishes in the course of arthritis. At all investigated time points (days 14, 32, and 55), only proinflammatory neuronal α-adrenergic effects on cytokine secretion were demonstrated (i.e., stimulation of IFN-γ and IL-6 and inhibition of TGF-β)., Conclusion: Sympathetic nerve fibers are rapidly lost in the spleen, and only proinflammatory α-adrenergic neuronal regulation of cytokine secretion takes place throughout the course of arthritis. These results support a predominance of a proinflammatory α-adrenergic sympathetic influence in arthritis., (© 2020 The Author(s) Published by S. Karger AG, Basel.)

The autonomic innervation of the skin includes different subsets of adrenergic and cholinergic fibers both in humans and animals. The corresponding chemical code is complex and often difficult to ascertain. Accordingly, a detailed histochemical description of skin autonomic fiber subtypes is lacking in humans. To characterize skin autonomic nerve subtypes may help to better understand the selective damage of specific skin autonomic fibers affecting human diseases such as the adrenergic fibers directed to skin vessels in Parkinson's disease or the cholinergic sudomotor fibers in Ross Syndrome. The present study aimed at characterizing subtypes of autonomic fibers in relation to their target organs by means of an immunofluorescent technique and confocal microscopy. We studied 8 healthy subjects (5 males and 3 females) aged 45 ± 2 (mean ± SE) years without predisposing causes for peripheral neuropathy or autonomic disorders. They underwent skin biopsy from proximal (thigh) and distal (leg) hairy skin. A combination of adrenergic (i.e. tyrosine-hydroxylase- TH and dopamine beta-hydroxylase- DbH) and cholinergic (vesicular acetylcholine transporter- VACHT) autonomic markers and neuropeptidergic (i.e. neuropeptide Y- NPY, calcitonin gene-related peptide- CGRP, substance P- SP, and vasoactive intestinal peptide- VIP) markers were used to characterize skin autonomic fibers. The analysed skin autonomic structures included: 58 sweat glands, 91 skin arterioles and 47 arrector pili muscles. Our results showed that all skin structures presented a sympathetic adrenergic but also cholinergic innervation although in different proportions. Sympathetic adrenergic fibers were particularly abundant around arterioles and arrector pili muscles whereas sympathetic cholinergic fibers were mainly found around sweat glands. Neuropeptides were differently expressed in sympathetic fibers: NPY were found in sympathetic adrenergic fibers around skin arterioles and very seldom sweat glands but not in adrenergic fibers of arrector pili muscles. By contrast CGRP, SP and VIP were expressed in sympathetic cholinergic fibers. Cholinergic fibers expressing CGRP, SP or VIP without TH or DbH staining were found in arterioles and arrector pili muscles and they likely represent parasympathetic fibers. In addition, all skin structures contained a small subset of neuropeptidergic fibers devoid of adrenergic and cholinergic markers with a likely sensory function. No major differences were found between males and females and proximal and distal sites. In summary hairy skin contains sympathetic adrenergic and cholinergic fibers differently distributed around skin structures with a specific distribution of neuropeptides. The autonomic skin innervation also contains a small amount of fibers, likely to be parasympathetic and sensory.

In the sympatho-adrenal system, angiotensin II (Ang II) acts as a key neuromodulatory component. At sympathetic nerve terminals, Ang II influences sympathetic transmission by enhancing norepinephrine (NE) synthesis, facilitating NE release and inhibiting NE uptake. Previously, it was demonstrated that tyrosine hydroxylase (TH) mRNA is trafficked to the distal axons of primary superior cervical ganglia (SCG) neurons, directed by a cis-acting regulatory element (i.e. zipcode) located in the 3'UTR of the transcript. Results of metabolic labeling studies established that the mRNA is locally translated. It was further shown that the axonal trafficking of the mRNA encoding the enzyme plays an important role in mediating dopamine (DA) and NE synthesis and may facilitate the maintenance of axonal catecholamine levels. In the present study, the hypothesis was tested that Ang II induces NE synthesis in rat primary SCG neurons via the modulation of the trafficking of the mRNAs encoding the catecholamine synthesizing enzymes TH and dopamine β-hydroxylase (DBH). Treatment of SCG neurons with the Ang II receptor type 1 (AT1R) agonist, L-162,313, increases the axonal levels of TH and DBH mRNA and protein and results in elevated NE levels. Conversely, treatment of rat SCG neurons with the AT1R antagonist, Eprosartan, abolished the L-162,313-mediated increase in axonal levels of TH and DBH mRNA and protein. In a first attempt to identify the proteins involved in the Ang II-mediated axonal transport of TH mRNA, we used a biotinylated 50-nucleotide TH RNA zipcode as bait in the affinity purification of TH zipcode-associated proteins. Mass spectrometric analysis of the TH zipcode ribonucleoprotein (RNP) complex immune-purified from SCG neurons led to the identification of 163 somal and 127 axonal proteins functionally involved in binding nucleic acids, the translational machinery or acting as subunits of cytoskeletal and motor proteins. Surprisingly, immune-purification of the TH axonal trafficking complex, results in the acquisition of DBH mRNA, suggesting that these mRNAs maybe transported to the axon together, possibly in the same RNP complex. Taken together, our results point to a novel mechanism by which Ang II participates in the regulation of axonal synthesis of NE by modulating the local trafficking and expression of TH and DBH, two key enzymes involved in the catecholamine biosynthetic pathway., (© Published 2019. This article is a U.S. Government work and is in the public domain in the USA.)

In recent years, the role of sympathetic nervous fibers in chronic inflammation has become increasingly evident. At the onset of inflammation, sympathetic activity is increased in the affected tissue. However, sympathetic fibers are largely absent from chronically inflamed tissue. Apparently, there is a very dynamic relationship between sympathetic innervation and the immune system in areas of inflammation, and hence a rapid and easy method for quantification of nerve fiber density of target organs is of great value to answer potential research questions. Currently, nervous fiber densities are either determined by tedious manual counting, which is not suitable for high throughput approaches, or by expensive automated processes relying on specialized software and high-end microscopy equipment. Usually, tyrosine hydroxylase (TH) is used as the marker for sympathetic fibers. In order to overcome the current quantification bottleneck with a cost-efficient alternative, an automated process was established and compared to the classic manual approach of counting TH-positive sympathetic fibers. Since TH is not exclusively expressed on sympathetic fibers, but also in a number of catecholamine-producing cells, a prerequisite for automated determination of fiber densities is to reliably distinct between cells and fibers. Therefore, an additional staining using peripherin exclusively expressed in nervous fibers as a secondary marker was established. Using this novel approach, we studied the spleens from a syndecan-3 knockout (SDC3KO) mouse line, and demonstrated equal results on SNS fiber density for both manual and automated counts (Manual counts: wildtype: 22.57 +/- 11.72 fibers per mm2; ko: 31.95 +/- 18.85 fibers per mm2; p = 0.05; Automated counts: wildtype: 31.6 +/- 18.98 fibers per mm2; ko: 45.49 +/- 19.65 fibers per mm2; p = 0.02). In conclusion, this new and simple method can be used as a high-throughput approach to reliably and quickly estimate SNS nerve fiber density in target tissues., Competing Interests: The authors have declared that no competing interests exist.

Several lines of evidence suggest that there is a close interrelation between the degree of noise in neural circuits and the activity of the norepinephrine (NE) system, yet the precise nexus between these aspects is far from being understood during human information processing and cognitive control in particular. We examine this nexus during response inhibition in n = 47 healthy participants. Using high-density EEG recordings, we estimate neural noise by calculating "1/ f noise" of those data and integrate these EEG parameters with pupil diameter data as an established indirect index of NE system activity. We show that neural noise is reduced when cognitive control processes to inhibit a prepotent/automated response are exerted. These neural noise variations were confined to the theta frequency band, which has also been shown to play a central role during response inhibition and cognitive control. There were strong positive correlations between the 1 /f neural noise parameter and the pupil diameter data within the first 250 ms after the Nogo stimulus presentation at centro-parietal electrode sites. No such correlations were evident during automated responding on Go trials. Source localization analyses using standardized low-resolution brain electromagnetic tomography show that inferior parietal areas are activated in this time period in Nogo trials. The data suggest an interrelation of NE system activity and neural noise within early stages of information processing associated with inferior parietal areas when cognitive control processes are required. The data provide the first direct evidence for the nexus between NE system activity and the modulation of neural noise during inhibitory control in humans. NEW & NOTEWORTHY This is the first study showing that there is a nexus between norepinephrine system activity and the modulation of neural noise or scale-free neural activity during inhibitory control in humans. It does so by integrating pupil diameter data with analysis of EEG neural noise.

Perivascular adipose tissue (PVAT) is no longer recognised as simply a structural support for the vasculature, and we now know that PVAT releases vasoactive factors which modulate vascular function. Since the discovery of this function in 1991, PVAT research is rapidly growing and the importance of PVAT function in disease is becoming increasingly clear. Obesity is associated with a plethora of vascular conditions; therefore, the study of adipocytes and their effects on the vasculature is vital. PVAT contains an adrenergic system including nerves, adrenoceptors and transporters. In obesity, the autonomic nervous system is dysfunctional; therefore, sympathetic innervation of PVAT may be the key mechanistic link between increased adiposity and vascular disease. In addition, not all obese people develop vascular disease, but a common feature amongst those that do appears to be the inflammatory cell population in PVAT. This review will discuss what is known about sympathetic innervation of PVAT, and the links between nerve activation and inflammation in obesity. In addition, we will examine the therapeutic potential of exercise in sympathetic stimulation of adipose tissue.

Whether sensory nerve can sense bone density or metabolic activity to control bone homeostasis is unknown. Here we found prostaglandin E2 (PGE2) secreted by osteoblastic cells activates PGE2 receptor 4 (EP4) in sensory nerves to regulate bone formation by inhibiting sympathetic activity through the central nervous system. PGE2 secreted by osteoblasts increases when bone density decreases as demonstrated in osteoporotic animal models. Ablation of sensory nerves erodes the skeletal integrity. Specifically, knockout of the EP4 gene in the sensory nerves or cyclooxygenase-2 (COX2) in the osteoblastic cells significantly reduces bone volume in adult mice. Sympathetic tone is increased in sensory denervation models, and propranolol, a β2-adrenergic antagonist, rescues bone loss. Furthermore, injection of SW033291, a small molecule to increase PGE2 level locally, significantly boostes bone formation, whereas the effect is obstructed in EP4 knockout mice. Thus, we show that PGE2 mediates sensory nerve to control bone homeostasis and promote regeneration.

Activation of short-chain free fatty acid receptors 3 (FFAR3) has been suggested to promote sympathetic outflow in postganglionic sympathetic neurons or hamper it by a negative coupling to N-type calcium (Ca V 2.2) channels. Heterogeneity of FFAR3 expression in sympathetic neurons, however, renders single neurons studies extremely time-consuming in wild-type mice. Previous studies demonstrated large variability of the degree of Ca V 2.2 channel inhibition by FFAR3 in a global population of rat sympathetic neurons. Therefore, we focused on a small subpopulation of mouse sympathetic neurons using an FFAR3 antibody and an Ffar3 reporter mouse to perform immunofluorescent and electrophysiological studies. Whole-cell patch-clamp recordings of identified FFAR3-expressing neurons from reporter mice revealed a 2.5-fold decrease in the Ca V 2.2-FFAR3 inhibitory coupling variability and 1.5-fold increase in the mean I Ca 2+ inhibition, when compared with unlabeled neurons from wild-type mice. Further, we found that the ablation of Ffar3 gene expression in two knockout mouse models led to a complete loss-of-function. Subpopulations of sympathetic neurons are associated with discrete functional pathways. However, little is known about the neural pathways of the FFAR3-expressing subpopulation. Our data indicate that FFAR3 is expressed primarily in neurons with a vasoconstrictor phenotype. Thus, fine-tuning of chemically-coded neurotransmitters may accomplish an adequate outcome.

Functional integrity of the regenerated tissues requires not only structural integrity but also vascularization and innervation. We previously demonstrated that the three-dimensional (3D) reconstructed eccrine sweat glands had similar structures as those of the native ones did, but whether the 3D reconstructed glands possessing vascularization and innervation was still unknown. In the study, Matrigel-embedded eccrine sweat gland cells were implanted under the inguinal skin. Ten weeks post-implantation, the vascularization, and innervation in the 10-week reconstructed eccrine sweat glands and native human eccrine sweat glands were detected by immunofluorescence staining. The results showed that the fluorescent signals of general neuronal marker protein gene product 9.5, adrenergic nerve fiber marker tyrosine hydroxylase, and cholinergic nerve fiber markers acetylcholinesterase and vasoactive intestinal peptide embraced the 3D reconstructed glands in circular patterns, as the signals appeared in native eccrine sweat glands. There were many CD31- and von Willebrand factor-positive vessels growing into the plugs. We demonstrated that the 3D reconstructed eccrine sweat glands were nourished by blood vessels, and we for the first time demonstrated that the engineering sweat glands were innervated by both cholinergic and adrenergic fibers. In conclusion, the 3D reconstructed eccrine sweat glands may have functions as the native ones do.

DOCA-salt and obesity-related hypertension are associated with inflammation and sympathetic nervous system hyperactivity. Prejunctional α 2 -adrenergic receptors (α 2 ARs) provide negative feedback to norepinephrine release from sympathetic nerves through inhibition of N-type Ca 2+ channels. Increased neuronal norepinephrine release in DOCA-salt and obesity-related hypertension occurs through impaired α 2 AR signaling; however, the mechanisms involved are unclear. Mesenteric arteries are resistance arteries that receive sympathetic innervation from the superior mesenteric and celiac ganglia (SMCG). We tested the hypothesis that macrophages impair α 2 AR-mediated inhibition of Ca 2+ channels in SMCG neurons from DOCA-salt and high-fat diet (HFD)-induced hypertensive rats. Whole cell patch-clamp methods were used to record Ca 2+ currents from SMCG neurons maintained in primary culture. We found that DOCA-salt, but not HFD-induced, hypertension caused macrophage accumulation in mesenteric arteries, increased SMCG mRNA levels of monocyte chemoattractant protein-1 and tumor necrosis factor-α, and impaired α 2 AR-mediated inhibition of Ca 2+ currents in SMCG neurons. α 2 AR dysfunction did not involve changes in α 2 AR expression, desensitization, or downstream signaling factors. Oxidative stress impaired α 2 AR-mediated inhibition of Ca 2+ currents in SMCG neurons and resulted in receptor internalization in human embryonic kidney-293T cells. Systemic clodronate-induced macrophage depletion preserved α 2 AR function and lowered blood pressure in DOCA-salt rats. HFD caused hypertension without obesity in Sprague-Dawley rats and hypertension with obesity in Dahl salt-sensitive rats. HFD-induced hypertension was not associated with inflammation in SMCG and mesenteric arteries or α 2 AR dysfunction in SMCG neurons. These results suggest that macrophage-mediated α 2 AR dysfunction in the mesenteric circulation may only be relevant to mineralocorticoid-salt excess. NEW & NOTEWORTHY Here, we identify a contribution of macrophages to hypertension development through impaired α 2 -adrenergic receptor (α 2 AR)-mediated inhibition of sympathetic nerve terminal Ca 2+ channels in DOCA-salt hypertensive rats. Impaired α 2 AR function may involve oxidative stress-induced receptor internalization. α 2 AR dysfunction may be unique to mineralocorticoid-salt excess, as it does not occur in obesity-related hypertension.

Withdrawal of nerve growth factor (NGF) from sympathetic neurons causes their apoptotic death. Activation of c-Jun NH2-terminal kinase (JNK) may contribute to this death by the induction and phosphorylation of pro-apoptotic Bcl-2 proteins, such as Bax, that are involved in cytochrome c release from mitochondria and reactive oxygen species (ROS) production. Induction of either JNK or ROS may stimulate the other, and both may regulate release of apoptogenic factors from the mitochondria. In order to discern the relationship between JNK and ROS in apoptosis, we treated NGF-deprived, mouse sympathetic neurons with a JNK inhibitor and examined the effect on several important apoptotic events. Block of JNK activation prevented induction of c-Jun expression and resulted in a dose-dependent, yet surprisingly modest, increase in cell survival after 48 h of NGF deprivation. JNK suppression was also not sufficient to prevent the elevation in ROS or the release of cytochrome c from the mitochondria in NGF-deprived sympathetic neurons. Bax deletion prevents apoptotic death of NGF-deprived neurons by preventing release of cytochrome c from their mitochondria. It also prevents increased ROS on NGF deprivation. However, we found that induction of c-Jun in cells lacking Bax was equivalent to that in wild-type neurons. Our results suggest that while JNK activation plays an important role in many forms of apoptosis, it may not be a crucial regulator of Bax-dependent events involved in the apoptotic death of mouse sympathetic neurons deprived of NGF and that ROS is not involved in its activation in these cells.

Cryotherapy is a therapeutic technique using ice or cold water applied to the skin to manage soft tissue trauma and injury. While beneficial, there are some potentially detrimental side effects, such as pronounced vasoconstriction and tissue ischemia that are sustained for hours post-treatment. This study tested the hypothesis that this vasoconstriction is mediated by 1) activation of post-synaptic α-adrenergic receptors and/or 2) activation of post-synaptic neuropeptide Y1 (NPY Y1) receptors. 8 subjects were fitted with a commercially available cryotherapy unit with a water perfused bladder on the lateral portion of the right calf. Participants were instrumented with four intradermal microdialysis probes beneath the bladder. The following conditions were applied at the four treatment sites: 1) control (Ringer solution), 2) combined post-synaptic β-adrenergic receptors and neuropeptide (NPY) Y 1 receptors blockade (P+B site), 3) combined post-synaptic α-adrenergic receptor, β-adrenergic receptor, and NPY Y 1 receptor blockade (Y+P+B site), and 4) blockade of pre-synaptic release of all neurotransmitters from the sympathetic nerves (BT site). Following thermoneutral baseline data collection, 1°C water was perfused through the bladder for 30min, followed by passive rewarming for 60min. Skin temperature (T skin ) fell from ~34°C to ~18.5°C during active cooling across all sites and there was no difference between sites (P>0.05 vs. control for each site). During passive rewarming T skin rose to a similar degree in all sites (P>0.05 relative to the end of cooling). In the first 20min of cooling %CVC was reduced at all sites however, this response was blunted in the BT and the Y+P+B sites (P>0.05 for all comparisons). By the end of cooling the degree of vasoconstriction was similar between sites with the exception that the reduction in %CVC in the Y+B+P site was less relative to the reduction in the control site. %CVC was unchanged in any of the sites during passive rewarming such that each remained similar to values obtained at the end of active cooling. These findings indicate that the initial vasoconstriction (i.e. within the 1st 20min) that occurs during cryotherapy induced local cooling is achieved via activation of post-synaptic α-adrenergic receptors; whereas nonadrenergic mechanisms predominate as the duration of cooling continues. The sustained vasoconstriction that occurs following cessation of the cooling stimulus does not appear to be related to activation of post-synaptic α-adrenergic receptors or NPY Y1 receptor., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Key Points: The effects of noradrenaline on excitatory synaptic transmission to regular spiking (excitatory) cells as well as regular spiking non-pyramidal and fast spiking (both inhibitory) cells in cortical layer 4 were studied in thalamocortical slice preparations, focusing on vertical input from thalamus and layer 2/3 in the mouse barrel cortex. Excitatory synaptic responses were suppressed by noradrenaline. However, currents induced by iontophoretically applied glutamate were not suppressed. Further, paired pulse ratio and coefficient of variation analysis indicated the site of action was presynaptic. Pharmacological studies indicated that the suppression was mediated by the α 2- adrenoceptor. Consistent with this, involvement of α 2A -adrenoceptor activation in the synaptic suppression in excitatory and inhibitory cells was confirmed by the use of α 2A -adrenoceptor knockout mice., Abstract: The mammalian neocortex is widely innervated by noradrenergic (NA) fibres from the locus coeruleus. To determine the effects of NA on vertical synaptic inputs to layer 4 (L4) cells from the ventrobasal thalamus and layer 2/3 (L2/3), thalamocortical slices were prepared and whole-cell recordings were made from L4 cells. Excitatory synaptic responses were evoked by electrical stimulation of the thalamus or L2/3 immediately above. Recorded cells were identified as regular spiking, regular spiking non-pyramidal or fast spiking cells through their firing patterns in response to current injections. NA suppressed (∼50% of control) excitatory vertical inputs to all cell types in a dose-dependent manner. The presynaptic site of action of NA was suggested by three independent studies. First, responses caused by iontophoretically applied glutamate were not suppressed by NA. Second, the paired pulse ratio was increased during NA suppression. Finally, a coefficient of variation (CV) analysis was performed and the resultant diagonal alignment of the ratio of CV -2 plotted against the ratio of the amplitude of postsynaptic responses suggests a presynaptic mechanism for the suppression. Experiments with phenylephrine (an α 1 -agonist), prazosin (an α 1 -antagonist), yohimbine (an α 2 -antagonist) and propranolol (a β-antagonist) indicated that suppression was mediated by the α 2 -adrenoceptor. To determine whether the α 2A -adrenoceptor subtype was involved, α 2A -adrenoceptor knockout mice were used. NA failed to suppress EPSCs in all cell types, suggesting an involvement of the α 2A -adrenoceptor. Altogether, we concluded that NA suppresses vertical excitatory synaptic connections in L4 excitatory and inhibitory cells through the presynaptic α 2A -adrenoceptor., (© 2017 The Authors. The Journal of Physiology © 2017 The Physiological Society.)

The salivary gland is rhythmically controlled by sympathetic nerve activation from the suprachiasmatic nucleus (SCN), which functions as the main oscillator of circadian rhythms. In humans, salivary IgA concentrations reflect circadian rhythmicity, which peak during sleep. However, the mechanisms controlling this rhythmicity are not well understood. Therefore, we examined whether the timing of parasympathetic (pilocarpine) or sympathetic (norepinephrine; NE) activation affects IgA secretion in the saliva. The concentrations of saliva IgA modulated by pilocarpine activation or by a combination of pilocarpine and NE activation were the highest in the middle of the light period, independent of saliva flow rate. The circadian rhythm of IgA secretion was weakened by an SCN lesion and Clock gene mutation, suggesting the importance of the SCN and Clock gene on this rhythm. Adrenoceptor antagonists blocked both NE- and pilocarpine-induced basal secretion of IgA. Dimeric IgA binds to the polymeric immunoglobulin receptor (pIgR) on the basolateral surface of epithelial cells and forms the IgA-pIgR complex. The circadian rhythm of Pigr abundance peaked during the light period, suggesting pIgR expression upon rhythmic secretion of IgA. We speculate that activation of sympathetic nerves during sleep may protect from bacterial access to the epithelial surface through enhanced secretion of IgA.

Hypoxia results in decreased arterial Po 2 , arterial chemoreflex activation, and compensatory increases in breathing, sympathetic outflow, and neuroendocrine secretions, including increased secretion of AVP, corticotropin-releasing hormone (CRH), adrenocorticotropin hormone (ACTH), and corticosterone. In addition to a brain stem pathway, including the nucleus tractus solitarius (nTS) and the rostral ventrolateral medulla (RVLM), medullary pathways to the paraventricular nucleus of the hypothalamus (PVN) contribute to chemoreflex responses. Experiments evaluated activation of specific cell phenotypes within the PVN following an acute hypoxic stimulus (AH; 2 h, 10% O 2 ) in conscious rats. Retrograde tracers (from spinal cord and RVLM) labeled presympathetic (PreS) neurons, and immunohistochemistry identified AVP- and CRH-immunoreactive (IR) cells. c-Fos-IR was an index of neuronal activation. Hypoxia activated AVP-IR (~6%) and CRH-IR (~15%) cells, but not PreS cells in the PVN, suggesting that sympathoexcitation during moderate AH is mediated mainly by a pathway that does not include PreS neurons in the PVN. Approximately 14 to 17% of all PVN cell phenotypes examined expressed neuronal nitric oxide synthase (nNOS-IR). AH activated only nNOS-negative AVP-IR neurons. In contrast ~23% of activated CRH-IR neurons in the PVN contained nNOS. In the median eminence, CRH-IR terminals were closely opposed to tanycyte processes and end-feet (vimentin-IR) in the external zone, where vascular NO participates in tanycyte retraction to facilitate neuropeptide secretion into the pituitary portal circulation. Results are consistent with an inhibitory role of NO on AVP and PreS neurons in the PVN and an excitatory role of NO on CRH secretion in the PVN and median eminence., (Copyright © 2017 the American Physiological Society.)

The cardiovascular system is extensively innervated by the autonomic nervous system, and the autonomic modulation including sympathetic innervation is crucial to the function of heart during normal and ischemic conditions. Severe myocardial ischemia could cause acute myocardial infarction, which is one of the leading diseases in the world. Thus studying the sympathetic modulation during ischemia could reduce the probability of myocardial infarction and further heart failure. The neurotransmitter ATP is released by myocardial cells during ischemia; however, the effect of ATP release remains elusive. We examined whether ATP released during ischemia functions as a neurotransmitter that activates sympathetic nerve in the heart. A novel technique of recording the sympathetic fiber calcium imaging in mouse cardiac tissue slices was used. We have applied the Cre/loxP system to specifically express GCaMP3, a genetically encoded calcium indicator, in the sympathetic nerve. Using this technique, we found that ATP released by myocardial cells through Pannexin-1 channel during ischemia could evoke calcium responses in cardiac sympathetic nerve fibers. Our study provides a new approach to study the cell and nerve interaction in the cardiac system, as well as a new understanding of ATP function during ischemia., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Background: Cuff and spared nerve injury (SNI) in the sciatic territory are widely used to model neuropathic pain. Because nociceptive information is first detected in skin, it is important to understand how alterations in peripheral innervation contribute to pain in each model. Over 16 weeks in male rats, changes in sensory and autonomic innervation of the skin were described after cuff and SNI using immunohistochemistry to label myelinated (neurofilament 200 positive-NF200+) and peptidergic (calcitonin gene-related peptide positive-CGRP+) primary afferents and sympathetic fibres (dopamine β-hydroxylase positive-DBH+), Results: Cuff and SNI caused an early loss and later reinnervation of NF200 and CGRP fibres in the plantar hind paw skin. In both models, DBH+ fibres sprouted into the upper dermis of the plantar skin 4 and 6 weeks after injury. Despite these similarities, behavioural pain measures were significantly different in each model. Sympathectomy using guanethidine significantly alleviated mechanical allodynia 6 weeks after cuff, when peak sympathetic sprouting was observed, having no effect at 2 weeks, when fibres were absent. In SNI animals, mechanical allodynia in the lateral paw was significantly improved by guanethidine at 2 and 6 weeks, and the development of cold hyperalgesia, which roughly paralleled the appearance of ectopic sympathetic fibres, was alleviated by guanethidine at 6 weeks. Sympathetic fibres did not sprout into the dorsal root ganglia at 2 or 6 weeks, indicating their unimportance to pain behaviour in these two models., Conclusions: Alterations in sympathetic innervation in the skin represents an important mechanism that contributes to pain in cuff and SNI models of neuropathic pain.

Objective: Density of sympathetic nerve fibers decreases in inflamed arthritic tissue tested by immunoreactivity towards tyrosine-hydroxylase (TH, catecholaminergic key enzyme). Since sympathetic nerve fibers may change phenotype from catecholaminergic to cholinergic (example: sweat glands), loss of nerve fibers may relate to undetectable TH. We aimed to investigate possible catecholaminergic-to-cholinergic transition of sympathetic nerve fibers in synovial tissue of animals with arthritis, and patients with rheumatoid arthritis (RA) and osteoarthritis (OA), and we wanted to find a possible transition factor., Methods: Nerve fibers were detected by immunofluorescence towards TH (catecholaminergic) and vesicular acetylcholine transporter (cholinergic). Co-culture experiments with sympathetic ganglia and lymphocytes or osteoclast progenitors were designed to find stimulators of catecholaminergic-to-cholinergic transition (including gene expression profiling)., Results: In mouse joints, an increased density of cholinergic relative to catecholaminergic nerve fibers appeared towards day 35 after immunization, but most nerve fibers were located in healthy joint-adjacent skin or muscle and almost none in inflamed synovial tissue. In humans, cholinergic fibers are more prevalent in OA synovial tissue than in RA. Co-culture of sympathetic ganglia with osteoclast progenitors obtained from healthy but not from arthritic animals induced catecholaminergic-to-cholinergic transition. Osteoclast mRNA microarray data indicated that leukemia inhibitory factor (LIF) is a candidate transition factor, which was confirmed in ganglia experiments, particularly, in the presence of progesterone., Conclusion: In humans and mice, catecholaminergic-to-cholinergic sympathetic transition happens in less inflamed tissue but not in inflamed arthritic tissue. Under healthy conditions, presence of cholinergic sympathetic nerve fibers may support the cholinergic anti-inflammatory influence recently described., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Rationale: The mechanisms leading to an expanded neutrophil and monocyte supply after stroke are incompletely understood., Objective: To test the hypothesis that transient middle cerebral artery occlusion (tMCAO) in mice leads to activation of hematopoietic bone marrow stem cells., Methods and Results: Serial in vivo bioluminescence reporter gene imaging in mice with tMCAO revealed that bone marrow cell cycling peaked 4 days after stroke (P<0.05 versus pre tMCAO). Flow cytometry and cell cycle analysis showed activation of the entire hematopoietic tree, including myeloid progenitors. The cycling fraction of the most upstream hematopoietic stem cells increased from 3.34%±0.19% to 7.32%±0.52% after tMCAO (P<0.05). In vivo microscopy corroborated proliferation of adoptively transferred hematopoietic progenitors in the bone marrow of mice with stroke. The hematopoietic system's myeloid bias was reflected by increased expression of myeloid transcription factors, including PU.1 (P<0.05), and by a decline in lymphocyte precursors. In mice after tMCAO, tyrosine hydroxylase levels in sympathetic fibers and bone marrow noradrenaline levels rose (P<0.05, respectively), associated with a decrease of hematopoietic niche factors that promote stem cell quiescence. In mice with genetic deficiency of the β3 adrenergic receptor, hematopoietic stem cells did not enter the cell cycle in increased numbers after tMCAO (naive control, 3.23±0.22; tMCAO, 3.74±0.33, P=0.51)., Conclusions: Ischemic stroke activates hematopoietic stem cells via increased sympathetic tone, leading to a myeloid bias of hematopoiesis and higher bone marrow output of inflammatory Ly6C(high) monocytes and neutrophils., (© 2014 American Heart Association, Inc.)

Glucagon-like peptide-1 (GLP-1) affects central autonomic neurons, including those controlling the cardiovascular system, thermogenesis, and energy balance. Preproglucagon (PPG) neurons, located mainly in the nucleus tractus solitarius (NTS) and medullary reticular formation, produce GLP-1. In transgenic mice expressing glucagon promoter-driven yellow fluorescent protein (YFP), these brainstem PPG neurons project to many central autonomic regions where GLP-1 receptors are expressed. The spinal cord also contains GLP-1 receptor mRNA but the distribution of spinal PPG axons is unknown. Here, we used two-color immunoperoxidase labeling to examine PPG innervation of spinal segments T1-S4 in YFP-PPG mice. Immunoreactivity for YFP identified spinal PPG axons and perikarya. We classified spinal neurons receiving PPG input by immunoreactivity for choline acetyltransferase (ChAT), nitric oxide synthase (NOS) and/or Fluorogold (FG) retrogradely transported from the peritoneal cavity. FG microinjected at T9 defined cell bodies that supplied spinal PPG innervation. The deep dorsal horn of lower lumbar cord contained YFP-immunoreactive neurons. Non-varicose, YFP-immunoreactive axons were prominent in the lateral funiculus, ventral white commissure and around the ventral median fissure. In T1-L2, varicose, YFP-containing axons closely apposed many ChAT-immunoreactive sympathetic preganglionic neurons (SPN) in the intermediolateral cell column (IML) and dorsal lamina X. In the sacral parasympathetic nucleus, about 10% of ChAT-immunoreactive preganglionic neurons received YFP appositions, as did occasional ChAT-positive motor neurons throughout the rostrocaudal extent of the ventral horn. YFP appositions also occurred on NOS-immunoreactive spinal interneurons and on spinal YFP-immunoreactive neurons. Injecting FG at T9 retrogradely labeled many YFP-PPG cell bodies in the medulla but none of the spinal YFP-immunoreactive neurons. These results show that brainstem PPG neurons innervate spinal autonomic and somatic motor neurons. The distributions of spinal PPG axons and spinal GLP-1 receptors correlate well. SPN receive the densest PPG innervation. Brainstem PPG neurons could directly modulate sympathetic outflow through their spinal inputs to SPN or interneurons., (Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Norepinephrine (NE) released from the sympathetic nerve endings is the main neurotransmitter controlling melatonin synthesis in the mammalian pineal gland. Although neuropeptide Y (NPY) co-exists with NE in the pineal sympathetic nerve fibers it also occurs in a population of non-adrenergic nerve fibers located in this gland. The role of NPY in pineal physiology is still enigmatic. The present study characterizes the effect of NPY on the depolarization-evoked 3H-NE release from the pig pineal explants. The explants of the pig pineal gland were loaded with 3H-NE in the presence of pargyline and superfused with Tyrode medium. They were exposed twice to the modified Tyrode medium containing 60 mM of K+ to evoke the 3H-NE release via depolarization. NPY, specific agonists of Y1- and Y2- receptors and pharmacologically active ligands of α2-adrenoceptors were added to the medium before and during the second depolarization. The radioactivity was measured in medium fractions collected every 2 minutes during the superfusion. NPY (0.1-10 μM) significantly decreased the depolarization-induced 3H-NE release. Similar effect was observed after the treatment with Y2-agonist: NPY13-36, but not with Y1-agonist: [Leu31,Pro34]-NPY. The tritium overflow was lower in the explants exposed to the 5 μM NPY and 1 μM rauwolscine than to rauwolscine only. The effects of 5 μM NPY and 0.05 μM UK 14,304 on the depolarization-evoked 3H-NE release were additive. The results show that NPY is involved in the regulation of NE release from the sympathetic terminals in the pig pineal gland, inhibiting this process via Y2-receptors.

Brainstem catecholaminergic neurons play key roles in the autonomic, neuroendocrine, and behavioral responses to glucoprivation, yet the functions of the individual groups are not fully understood. Adrenergic C3 neurons project widely throughout the brain, including densely to sympathetic preganglionic neurons in the spinal cord, yet their function is completely unknown. Here we demonstrate in rats that optogenetic stimulation of C3 neurons induces sympathoexcitatory, cardiovasomotor functions. These neurons are activated by glucoprivation, but unlike the C1 cell group, not by hypotension. The cardiovascular activation induced by C3 neurons is less than that induced by optogenetic stimulation of C1 neurons; however, combined stimulation produces additive sympathoexcitatory and cardiovascular effects. The varicose axons of C3 neurons largely overlap with those of C1 neurons in the region of sympathetic preganglionic neurons in the spinal cord; however, regional differences point to effects on different sympathetic outflows. These studies definitively demonstrate the first known function of C3 neurons as unique cardiovasomotor stimulatory cells, embedded in the brainstem networks regulating cardiorespiratory activity and the response to glucoprivation., (Copyright © 2014 the authors 0270-6474/14/3415110-13$15.00/0.)

We investigated the distribution of CARTp(55-102) in rat lower urinary tract and evaluated its effect on urinary bladder function in vitro. Immunohistochemistry and a vertical isolated tissue bath system were used. Neurons, clusters of nonneuronal endocrine cells, and nerve fibers stained positive for CARTp(55-102) in young adult rat urinary bladder. The CARTp-expressing neuronal elements were nitric oxide synthase (NOS)- and tyrosine hydroxylase (TH)-IR, whereas all nonneuronal CARTp-IR elements stained positively only for TH (100 %). In isolated bladder strips, CARTp significantly increased the amplitude of electric field stimulation (EFS)-induced detrusor contractions at stimulation frequencies ≤12.5 Hz (p ≤ 0.001) as well as amplitude and frequency of spontaneous phasic urinary bladder smooth muscle (UBSM) contractions (p ≤ 0.05). The responses to CARTp stimulation were dose-dependent and increased in the presence of the urothelium. To determine if the CARTp increase in nerve-mediated contractions may involve an action of CARTp on specific neural pathways, we blocked cholinergic, purinergic, and adrenergic pathways and determined CARTp actions on EFS-medicated contractions. CARTp enhancement of EFS-mediated contractions does not involve alteration in purinergic, adrenergic, or cholinergic pathways. The study demonstrates that CARTp(55-102) is highly expressed in rat urinary bladder. CARTp increased the amplitude of EFS-induced detrusor contractions as well as the amplitude and frequency of spontaneous phasic urinary bladder smooth muscle contractions. We conclude that CARTp may alter the release of compounds from the urothelium that leads to an enhancement of UBSM contractility/excitability.

The roles of α2-adrenergic receptors located in the spinal cord in the regulation of blood glucose levels were studied in imprinting control region (ICR) mice. Mice were treated intrathecally (i.t.) with clonidine or yohimbine, and the blood glucose levels were measured at 0, 30, 60 and 120min after i.t. administration. The i.t. injection with clonidine caused a pronounced elevation of the blood glucose levels in a dose-dependent manner. Clonidine-induced hyperglycemic effect was dose-dependently attenuated by i.t. pretreatment with yohimbine. Furthermore, plasma insulin level was attenuated by clonidine, and yohimbine pretreatment reversed partially, but significantly, clonidine-induced down-regulation of the plasma insulin level. I.t. pretreatment with pertussis toxin (PTX) almost abolished the hyperglycemic effect induced by clonidine. PTX pretreatment reversed the induced down-regulation of the insulin level. In addition, i.t. pretreatment with N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP-4) or intraperitoneal (i.p.) pretreatment with mifepristone, hexamethonium and 6-hydroxydopamine (6-OHDA) attenuated the hyperglycemic effect induced by clonidine. I.t. injected clonidine significantly increased plasma corticosterone level. The elevated blood glucose level induced by clonidine was significantly decreased in adrenalectomized (ADX) mice. Our results suggest that the α2-adrenergic receptors located in the spinal cord play important roles for the elevation of the blood glucose level. The hyperglycemic effect induced by clonidine appears to be mediated by a reduction of the plasma insulin level. In addition, glucocortioid system appears to be involved in clonidine-induced hyperglycemic effect. Furthermore, the clonidine-induced hyperglycemia appears to be mediated via activating the spinal nerves or peripheral sympathetic nervous system., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Background: To determine the yet unknown relation between thoracic aortic dissection (TAD) and sympathetic nervous system activity., Methods: Variables such as electrocardiography, blood pressure, respiratory activity, postganglionic muscle sympathetic nerve activity (MSNA), plasma norepinephrine, tyrosine hydroxylase-positive nerve fiber density, and growth-associated protein 43-positive nerve fiber density were detected and statistically analyzed., Results: TAD Patients showed a significant lower R-R interval variance and higher blood pressure, heart rate, respiratory rate, MSNA, plasma norepinephrine (reflecting elevated sympathetic nervous system [SNS] activity), higher tyrosine hydroxylase, growth-associated protein 43-positive nerve fiber density (reflecting sympathetic sprouting and innervation) than those of the control group., Conclusions: In TAD patients, both overall and regional aortic SNS activities are elevated., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Voltammetric measurements of catecholamines in the medial prefrontal cortex (mPFC) are infrequent because of lack of chemical selectivity between dopamine and norepinephrine and their overlapping anatomical inputs. Here, we examined the contribution of norepinephrine to the catecholamine release in the mPFC evoked by electrical stimulation of the ventral tegmental area (VTA). Initially, electrical stimulation was delivered in the midbrain at incremental depths of -5 to -9.4 mm from bregma while catecholamine release was monitored in the mPFC. Although catecholamine release was observed at dorsal stimulation sites that may correspond to the dorsal noradrenergic bundle (DNB, containing noradrenergic axonal projections to the mPFC), maximal release was evoked by stimulation of the VTA (the source of dopaminergic input to the mPFC). Next, VTA-evoked catecholamine release was monitored in the mPFC before and after knife incision of the DNB, and no significant changes in the evoked catecholamine signals were found. These data indicated that DNB fibers did not contribute to the VTA-evoked catecholamine release observed in the mPFC. Finally, while the D2-receptor antagonist raclopride significantly altered VTA-evoked catecholamine release, the α₂-adrenergic receptor antagonist idazoxan did not. Specifically, raclopride reduced catecholamine release in the mPFC, opposite to that observed in the striatum, indicating differential autoreceptor regulation of mesocortical and mesostriatal neurons. Together, these findings suggest that the catecholamine release in the mPFC arising from VTA stimulation was predominately dopaminergic rather than noradrenergic., (Copyright © 2013 Wiley Periodicals, Inc.)

Alzheimer's disease (AD) is characterized by amyloid-β (Aβ) plaques, hyperphosphorylated tau neurofibrillary tangles, and cholinergic dysfunction. Cholinergic degeneration can be mimicked in rats by lesioning medial septum cholinergic neurons. Hippocampal cholinergic denervation disrupts retrograde nerve growth factor (NGF) transport, leading to its accumulation, which subsequently triggers sprouting of noradrenergic sympathetic fibers from the superior cervical ganglia into hippocampus. Previously we reported that coincident with noradrenergic sprouting is the partial reinnervation of hippocampus with cholinergic fibers and the maintenance of a M1 muscarinic acetylcholine receptor (M1 mAChR) dependent long-term depression at CA3-CA1 synapses that is lost in the absence of sprouting. These findings suggest that sympathetic sprouting and the accompanying cholinergic reinnervation maintains M1 mAChR function. Importantly, noradrenergic sympathetic and cholinergic sprouting have been demonstrated in human postmortem AD hippocampus. Furthermore, M1 mAChRs are a recent focus as a therapeutic target for AD given their role in cognition and non-amyloidogenic processing of amyloid-β protein precursor (AβPP). Here we tested the hypotheses that noradrenergic sympathetic sprouting is triggered by NGF, that sprouting maintains non-amyloidogenic AβPP processing, and that sprouting is prevented by intrahippocampal Aβ42 infusion. We found that NGF stimulates sprouting, that sprouting maintains non-amyloidogenic AβPP processing, and that Aβ42 is not only toxic to central cholinergic fibers innervating hippocampus but it prevents and reverses noradrenergic sympathetic sprouting and the accompanying cholinergic reinnervation. These findings reiterate the clinical implications of sprouting as an innate compensatory mechanism and emphasize the importance of M1 mAChRs as an AD therapeutic target.

We performed a two-part study to determine the roles of endothelial nitric oxide synthase (eNOS) and the vasoconstrictor nerves neurotransmitters noradrenaline (NA) and neuropeptide Y (NPY) in the cutaneous vasodilator response to local skin warming. Forearm skin sites were instrumented with intradermal microdialysis fibres, local heaters, and laser-Doppler flow (LDF) probes. Sites were locally heated from 34 to 42°C. LDF was expressed as cutaneous vascular conductance (CVC; LDF/mean arterial pressure). In Part I, we tested whether sympathetic noradrenergic nerves acted via eNOS. In 8 male participants, treatments were as follows: 1) untreated; 2) bretylium tosylate (BT), preventing sympathetic neurotransmitter release; 3) l-NAA to inhibit eNOS; and 4) combined BT+l-NAA. At treated sites, the initial peak response was markedly reduced, and the plateau phase response to 35min of local warming was also reduced (P<0.05), which was not different among those sites (P>0.05). In Part II, we tested whether NA and NPY were involved in the vasodilator response to local warming. In Part IIa, treatments were: 1) untreated; 2) propranolol and yohimbine to antagonize α- and β-receptors; 3) l-NAA; and 4) combined propranolol, yohimbine, and l-NAA. In Part IIb, conditions were: 1) untreated; 2) BIBP to antagonize Y1-receptors; 3) l-NAA; and 4) combined BIBP and l-NAA. All treatments caused a reduction in the initial peak and plateau responses to local skin warming (P<0.05). The results of Part II indicate that both NA and NPY play roles in the cutaneous vasodilator response and their actions are achieved via eNOS. These data indicate that NA and NPY are involved in the initial, rapid rise in skin blood flow at the onset of local skin warming. However, their vasodilator actions in response to local skin warming appears to be manifested through eNOS., (© 2013.)

Neurotransmitters are identified to be endogenous chemicals and act on neurons to transmit signals to each other or to a target cell across synapse. They are involved in many brain functions including analgesia, reward, food intake, metabolism, reproduction, social behaviors, learning, and memory. Recently, sympathetic nerve fibers were detected in many solid tumors including gastrointestinal cancer, supporting the idea that neural system has effects on tumor progression. Neurotransmitters were secreted from the sympathetic nerve fibers and subsequently infiltrated into tumor tissues. Further studies disclosed the different mechanisms of various kinds of neurotransmitters in the progression of carcinogenesis, including tumor cell proliferation, angiogenesis, and tumor invasion and metastasis. Neurotransmitters are mainly subdivided into four types, amino acids, monoamines, peptides, and others, each of which contains multiple chemicals. For this reason, we cannot describe each in detail. In this review, we will focus on several important neurotransmitters including tachykinis, neuropeptide Y, and b-adrenergic receptors. How they function and their crosstalks with the immune system in the progression, especially the metastasis of gastrointestinal cancer, will be described. Finally, we will summarize the clinical implications in the treatment of gastrointestinal cancer.

Object: To test the hypothesis that angiotensin II (Ang II) could enhance noradrenaline (NA) release from sympathetic nerve endings of the aorta thus contributing to the up-regulation of matrix metalloproteinase 2 (MMP-2) during the formation of aortic dissection (AD)., Methods: Ang II, NA, MMP-2, MMP-9 of the aorta sample obtained during operation from aortic dissection patients were detected by High Performance Liquid Chromatography and ELISA and compared with controls. Isotope labelling method was used to test the impact of exogenous Ang II and noradrenaline on the NA release and MMP-2, MMP-9 expression on Sprague Dawley (SD) rat aorta rings in vitro. Two kidneys, one clip, models were replicated for further check of that impact in SD rats in vivo., Results: The concentration of Ang II, MMP-2, 9 was increased and NA concentration was decreased in aorta samples from AD patients. Exogenous Ang II enhanced while exogenous NA restrained NA release from aortic sympathetic endings. The Ang II stimulated NA release and the following MMP-2 up-regulation could be weakened by Losartan and chemical sympathectomy. Beta blocker did not influence NA release but down-regulated MMP-2. Long term in vivo experiments confirmed that Ang II could enhance NA release and up-regulate MMP-2., Conclusions: AD is initiated by MMP-2 overexpression as a result of increased NA release from sympathetic nervous endings in response to Ang II. This indicates an interaction of RAS and SAS during the formation of AD.

Objective: To investigate neuronal remodeling processes in the uterine innervation, particularly a remodeling of sympathetic nerve fibers, as well as the role of estrogen in this modulation in adenomyosis., Design: Retrospective case-control study., Setting: University hospital endometriosis center., Patient(s): Forty-two patients with histologically proven adenomyosis and 19 patients without adenomyosis., Intervention(s): Endometrial and myometrial tissue were immunohistochemically analyzed to further characterize the uterine innervation., Main Outcome Measure(s): Immunohistochemical analysis was used to identify PGP 9.5-, substance P-, and tyrosine hydroxylase-positive nerve fibers. The expression of the aromatase cytochrome P450 was evaluated in uterine tissue, and the expression of the estrogen receptor (ER) -α and ERβ in uterine nerve fibers was analyzed., Result(s): Adenomyotic lesions are not innervated. The density of sympathetic nerve fibers in the myometrium of women with adenomyosis is reduced when compared with the nonadenomyosis group. The aromatase expression in the myometrium of women with adenomyosis was increased when compared with the control group. The ERα/ERβ ratio is in trend shifted to the ERα side in the myometrial tyrosine hydroxylase-positive nerve fibers in adenomyosis compared to the controls., Conclusion(s): The disruption of the modulation of the uterine sympathetic innervation seems to be an important aspect in the pathogenesis of adenomyosis. Estrogen and its receptors seem to play a crucial role in the depletion of myometrial sympathetic nerve fibers., (Copyright © 2013 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.)

The transcription factor STAT3 has been implicated in axon regeneration. Here we investigate a role for STAT3 in sympathetic nerve sprouting after myocardial infarction (MI) - a common injury in humans. We show that NGF stimulates serine phosphorylation (S727) of STAT3 in sympathetic neurons via ERK1/2, in contrast to cytokine phosphorylation of Y705. Maximal sympathetic axon regeneration in vitro requires phosphorylation of both S727 and Y705. Furthermore, cytokine signaling is necessary for NGF-induced sympathetic nerve sprouting in the heart after MI. Transfection studies in neurons lacking STAT3 suggest two independent pools of STAT3, phosphorylated on either S727 or Y705, that regulate sympathetic regeneration via both transcriptional and non-transcriptional means. Additional data identify STAT3-microtubule interactions that may complement the well-characterized role of STAT3 stimulating regeneration associated genes. These data show that STAT3 is critical for sympathetic axon regeneration in vitro and in vivo, and identify a novel non-transcriptional mode of action., (© 2013.)

Although chronic pain is the most common symptom of arthritis, relatively little is known about the mechanisms driving it. Recently, a sprouting of autonomic sympathetic fibers into the upper dermis of the skin, an area that is normally devoid of them, was found in the skin following chronic inflammation of the rat hindpaw. While this sprouting only occurred when signs of joint and bone damage were present, it remained to be clarified whether it was a consequence of the chronic inflammation of the skin or of the arthritis and whether it also occurred in the joint. In the present study, we used a model of arthritis in which complete Freund's adjuvant (CFA) was injected into the rat ankle joint. At 4 weeks following CFA treatment, there was an increase in sympathetic and peptidergic fiber density in the ankle joint synovium. We also observed a sympathetic, but not peptidergic, fiber sprouting in the skin over the joint, which may be a consequence of the increased levels of mature nerve growth factor levels in skin, as revealed by Western blot analysis. The pharmacological suppression of sympathetic fiber function with systemic guanethidine significantly decreased the pain-related behavior associated with arthritis. Guanethidine completely suppressed the heat hyperalgesia and attenuated mechanical and cold hypersensitivity. These results suggest that transmitters released from the sprouted sympathetic fibers in the synovial membrane and upper dermis contribute to the pain-related behavior associated with arthritis. Blocking the sympathetic fiber sprouting may provide a novel therapeutic approach to alleviate pain in arthritis.

This work studies the morphological changes taking place in the goat omasum during prenatal development, using scanning electron microscope, light microscopy and immunohistochemical analysis. A total of 140 goat embryos and fetuses were used, from the first stages of prenatal life until birth. Differentiation of the omasum as a separate compartment of the primitive gastric tube was observed at 35 days of prenatal life ([crown-rump length (CRL)] 3 cm, 23% gestation). By 38 days (CRL 4.3 cm, 25% gestation) the omasal wall comprised three layers: an internal epithelial layer, a middle layer of pluripotential blastemic tissue and an external layer or serosa. Omasal laminae appeared in the following order: primary at 38 days (CRL 4.3 cm, 25% gestation), secondary at 50 days (CRL 7.7 cm, 33% gestation), tertiary at 59 days (CRL 12 cm, 39% gestation) and quaternary at 64 days (CRL 13.5 cm, 43% gestation). Neuroendocrine cells were detected by synaptophysin (SYP) at 52 days (CRL 8 cm, 35% gestation), while glial cell markers (glial fibrillary acidic protein - GFAP, and vimentin-VIM) were observed at 64 days (CRL 13.5 cm, 43% gestation) and 38 days (CRL 4.3 cm, 25% gestation), respectively. Sympathetic and parasympathetic nerve fibers and nerve bodies were detected via neuropeptide Y (NPY) and vasoactive intestinal polypeptide (VIP) at 95 days (CRL 20 cm, 63% gestation). In conclusion, prenatal development of the omasum - like that of the rumen - appears to take place somewhat earlier in goats than in sheep or cattle, but at a similar stage to that reported in deer.

Axonal protein synthesis is a complex process involving selective mRNA localization and translational regulation. In this study, using in situ hybridization and metabolic labeling, we show that the mRNAs encoding eukaryotic translation initiation factors eIF2B2 and eIF4G2 are present in the axons of rat sympathetic neurons and are locally translated. We also report that a noncoding microRNA, miR16, modulates the axonal expression of eIF2B2 and eIF4G2. Transfection of axons with precursor miR16 and anti-miR16 showed that local miR16 levels modulated axonal eIF2B2 and eIF4G2 mRNA and protein levels, as well as axon outgrowth. siRNA-mediated knock-down of axonal eIF2B2 and eIF4G2 mRNA also resulted in a significant decrease in axonal eIF2B2 and eIF4G2 protein. Moreover, results of metabolic labeling studies showed that downregulation of axonal eIF2B2 and eIF4G2 expression also inhibited local protein synthesis and axon growth. Together, these data provide evidence that miR16 mediates axonal growth, at least in part, by regulating the local protein synthesis of eukaryotic translation initiation factors eIF2B2 and eIF4G2 in the axon.

Objective: This study aimed to test whether peripheral α-synuclein staining might be useful for pure autonomic failure (PAF) diagnosis, helping to differentiate degenerative from acquired peripheral autonomic neuropathy., Methods: We studied 21 patients with chronic peripheral autonomic neuropathy showing sympathetic and parasympathetic involvement as confirmed by cardiovascular reflexes and microneurography from the peroneal nerve. Twelve patients showed a specific cause of neuropathy (acquired autonomic neuropathy) whereas 9 had no specific acquired causes fulfilling the diagnostic criteria for PAF. Fifteen matched healthy subjects served as controls. Subjects underwent skin biopsy from thigh and leg to study skin innervation and phosphorylated α-synuclein deposits in the peripheral axons., Results: Somatic and autonomic skin innervations were significantly decreased in patients with peripheral autonomic neuropathy compared to controls. No differences were found between acquired autonomic neuropathy and PAF. The deposits of α-synuclein were not found in controls but served to distinguish acquired from degenerative autonomic peripheral neuropathy: all patients with PAF showed α-synuclein deposits, which were absent in patients with acquired autonomic neuropathy. Colocalization study disclosed α-synuclein neuritic inclusions in the postganglionic sympathetic adrenergic and cholinergic nerve fibers., Conclusions: Our study demonstrated that a search for neuritic inclusions of phosphorylated α-synuclein in the skin sympathetic nerve fibers could provide a sensitive in vivo biomarker for degenerative peripheral autonomic neuropathy and may shed more light on the pathogenesis of PAF.

We tested the hypothesis that pharmacological blockade of α(1)-adrenoreceptors (by prazosin), at rest and during steady-state dynamic exercise, would impair cerebral autoregulation and result in cerebral vasodilatation in healthy humans. In 10 subjects, beat-to-beat mean arterial pressure and mean middle cerebral artery blood velocity were determined at rest and during low (Ex90) and moderate workload (Ex130) on an upright bicycle ergometer without and with prazosin. Plasma noradrenaline concentrations increased significantly from rest to Ex130 during control conditions (from 1.8 ± 0.2 to 3.2 ± 0.3 pmol (ml plasma)(-1)). In the control conditions, the transfer function gain between mean arterial pressure and mean middle cerebral artery blood velocity in the low-frequency range was decreased at Ex90 (P = 0.035) and Ex130 (P = 0.027) from rest. A significant increase in critical closing pressure (CCP) was also observed in the control conditions from rest to Ex90 to Ex130 (from 18 ± 3 to 24 ± 4 to 31 ± 4 mmHg). An average of 74 ± 2% blockade of blood pressure response was achieved with oral prazosin. Following blockade, plasma noradrenaline concentrations further increased at rest and during Ex130 from the control value (from 2.6 ± 0.3 to 4.4 ± 0.5 pmol (ml plasma)(-1)). Prazosin also resulted in an increase in low-frequency gain (P < 0.003) compared with the control conditions. Prazosin blockade abolished the increases in CCP during Ex130 and increased the cerebrovascular conductance index (P = 0.018). These data indicate that in the control conditions a strengthening of cerebral autoregulation occurred with moderate dynamic exercise that is associated with an increase in CCP as a result of the exercise-mediated augmentation of sympathetic activity. Given that α(1)-adrenergic receptor blockade attenuated the increase in dynamic cerebral autoregulation and CCP, we conclude that increases in sympathetic activity have a role in establishing cerebral vascular tone in humans.

Primary palmar hyperhidrosis (PPH) is a condition characterized by high levels of palmar perspiration in excess of physiological need. The etiopathogenesis of PPH is thought to be related to hyperactivity of the sympathetic system, but the exact mechanism is still obscure. The aim of this study was to observe the ultrastructure of the thoracic sympathetic nerves and measure the expression of neuregulin-1 (Nrg-1) in thoracic sympathetic nerve tissue in patients with PPH relative to control subjects. Samples of T3 sympathetic ganglia were obtained from 58 subjects: 30 PPH patients who underwent endoscopic thoracic sympathectomy and 28 control subjects who underwent pleurectomy for chronic empyema. The ultrastructure of the myelin sheath of the sympathetic axons was observed using electron microscopy, and the thickness of the myelin sheath was compared between the two groups. Expression of Nrg-1 mRNA in thoracic sympathetic nerve tissue was evaluated using reverse transcription-polymerase chain reaction analysis. Subjects in the hyperhidrosis group had a significantly greater average myelin thickness and a significantly lower g-ratio relative to the control group. The hyperhidrosis group had significantly higher relative expression of Nrg-1 mRNA in thoracic sympathetic nerve tissue. Hypermyelination of the thoracic sympathetic axons is probably one pathogenetic mechanism underlying PPH. Nrg-1 is likely to be an important cause of hypermyelination in thoracic sympathetic axons in patients with PPH., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Endocannabinoids play a crucial neuromodulator role in both physiological and pathological states in various brain regions including the prefrontal cortex (PFC). We examined, whether presynaptic cannabinoid receptors are involved in the modulation of basal and electrical field stimulation-evoked [³H]norepinephrine ([³H]NE) release from rat PFC slices. WIN55,212-2, a nonselective CB₁ receptor (CB₁R) agonist, inhibited the electrical stimulation-evoked efflux of [³H]NE in a concentration-dependent fashion, which was antagonized by the CB₁R antagonist/inverse agonist, AM251 (1 μM). Idazoxan, a selective α₂-adrenoceptor antagonist, augmented the evoked [³H]NE release. In the presence of idazoxan, the effect of WIN55,212-2 was exacerbated or attenuated, depending on the applied concentration and stimulation frequency. Moreover their combined, but not individual application elicited a depressive-like phenomenon in the forced-swim test. These data were bolstered with fluorescent and confocal microscopy analysis, which revealed that CB₁R immunoreactivity co-localized with dopamine-β-hydroxylase positive (i.e. noradrenergic) fibers and the inhibitory α(2A) adrenergic autoreceptors (α(2A)R) in the PFC. Furthermore, idazoxan triggered a decrease in CB₁R density in the PFC, suggesting that high extracellular level of norepinephrine downregulates CB₁Rs., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Nucleotides released within the heart under pathological conditions can be involved in cardioprotection or cardiac fibrosis through the activation purinergic P2Y(2) and P2Y(6) receptors, respectively. We previously demonstrated that adult P2Y(4)-null mice display a microcardia phenotype related to a cardiac angiogenic defect. To evaluate the functional consequences of this defect, we performed here a combination of cardiac monitoring and exercise tests. We investigated the exercise capacity of P2Y(4) wild-type and P2Y(4)-null mice in forced swimming and running tests. Analysis of their stress, locomotion, and resignation was realized in open field, black and white box, and tail suspension experiments. Exercise-induced cardiac hypertrophy was evaluated after repeated and prolonged exercise in P2Y(4) wild-type and P2Y(4)-null hearts. We showed that P2Y(4)-null mice have a lower exercise capacity in both swimming and treadmill tests. This was not related to decreased motivation or increased stress, since open field, white and black box, and mouse tail suspension tests gave comparable results in P2Y(4) wild-type and P2Y(4)-null mice. Heart rate and blood pressure rose normally in P2Y(4)-null swimming mice equipped with a telemetric implant. On the contrary, we observed a delayed recovery of postexercise blood pressure after exercise in P2Y(4)-null mice. The heart rate increment in response to catecholamines was also similar in P2Y(4) wild-type and P2Y(4)-null implanted mice, which is consistent with a similar level of cardiac β-receptor expression. Interestingly, the heart of P2Y(4)-null mice displayed a reduced sympathetic innervation associated with a decreased norepinephrine level. We also demonstrated that exercise-induced cardiac hypertrophy was lower in P2Y(4)-null mice after repeated and prolonged exercise. This was associated with a lower increase in cardiomyocyte size and microvessel density. In conclusion, besides its role in cardiac development, P2Y(4) receptor could constitute an important regulator of acute and chronic response to exercise.

Background: Severe TBI, defined as a Glasgow Coma Scale ≤ 8, increases intracranial pressure and activates the sympathetic nervous system. Sympathetic hyperactivity after TBI manifests as catecholamine excess, hypertension, abnormal heart rate variability, and agitation, and is associated with poor neuropsychological outcome. Propranolol and clonidine are centrally acting drugs that may decrease sympathetic outflow, brain edema, and agitation. However, there is no prospective randomized evidence available demonstrating the feasibility, outcome benefits, and safety for adrenergic blockade after TBI., Methods/design: The DASH after TBI study is an actively accruing, single-center, randomized, double-blinded, placebo-controlled, two-arm trial, where one group receives centrally acting sympatholytic drugs, propranolol (1 mg intravenously every 6 h for 7 days) and clonidine (0.1 mg per tube every 12 h for 7 days), and the other group, double placebo, within 48 h of severe TBI. The study uses a weighted adaptive minimization randomization with categories of age and Marshall head CT classification. Feasibility will be assessed by ability to provide a neuroradiology read for randomization, by treatment contamination, and by treatment compliance. The primary endpoint is reduction in plasma norepinephrine level as measured on day 8. Secondary endpoints include comprehensive plasma and urine catecholamine levels, heart rate variability, arrhythmia occurrence, infections, agitation measures using the Richmond Agitation-Sedation Scale and Agitated Behavior scale, medication use (anti-hypertensive, sedative, analgesic, and antipsychotic), coma-free days, ventilator-free days, length of stay, and mortality. Neuropsychological outcomes will be measured at hospital discharge and at 3 and 12 months. The domains tested will include global executive function, memory, processing speed, visual-spatial, and behavior. Other assessments include the Extended Glasgow Outcome Scale and Quality of Life after Brain Injury scale. Safety parameters evaluated will include cardiac complications., Discussion: The DASH After TBI Study is the first randomized, double-blinded, placebo-controlled trial powered to determine feasibility and investigate safety and outcomes associated with adrenergic blockade in patients with severe TBI. If the study results in positive trends, this could provide pilot evidence for a larger multicenter randomized clinical trial. If there is no effect of therapy, this trial would still provide a robust prospective description of sympathetic hyperactivity after TBI., Trial Registration: ClinicalTrials.gov NCT01322048.

The multistep sequence leading to leukocyte migration is thought to be locally regulated at the inflammatory site. Here, we show that broad systemic programs involving long-range signals from the sympathetic nervous system (SNS) delivered by adrenergic nerves regulate rhythmic recruitment of leukocytes in tissues. Constitutive leukocyte adhesion and migration in murine bone marrow (BM) and skeletal-muscle microvasculature fluctuated with circadian peak values at night. Migratory oscillations, altered by experimental jet lag, were implemented by perivascular SNS fibers acting on β-adrenoreceptors expressed on nonhematopoietic cells and leading to tissue-specific, differential circadian oscillations in the expression of endothelial cell adhesion molecules and chemokines. We showed that these rhythms have physiological consequences through alteration of hematopoietic cell recruitment and overall survival in models of septic shock, sickle cell vaso-occlusion, and BM transplantation. These data provide unique insights in the leukocyte adhesion cascade and the potential for time-based therapeutics for transplantation and inflammatory diseases., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Objective: Many forms of arthritis are accompanied by significant chronic joint pain. This study was undertaken to investigate whether there is significant sprouting of sensory and sympathetic nerve fibers in the painful arthritic knee joint and whether nerve growth factor (NGF) drives this pathologic reorganization., Methods: A painful arthritic knee joint was produced by injection of Freund's complete adjuvant (CFA) into the knee joint of young adult mice. CFA-injected mice were then treated systemically with vehicle or anti-NGF antibody. Pain behaviors were assessed, and at 28 days following the initial CFA injection, the knee joints were processed for immunohistochemistry analysis using antibodies against calcitonin gene-related peptide (CGRP; sensory nerve fibers), neurofilament 200 kd (NF200; sensory nerve fibers), growth-associated protein 43 (GAP-43; sprouted nerve fibers), tyrosine hydroxylase (TH; sympathetic nerve fibers), CD31 (endothelial cells), or CD68 (monocyte/macrophages)., Results: In CFA-injected mice, there was a significant increase in the density of CD68+ macrophages, CD31+ blood vessels, and CGRP+, NF200+, GAP-43+, and TH+ nerve fibers in the synovium, as well as a significant increase in joint pain-related behaviors. None of these findings were observed in sham-injected mice. Administration of anti-NGF reduced these pain-related behaviors and the ectopic sprouting of nerve fibers, but had no significant effect on the increase in density of CD31+ blood vessels or CD68+ macrophages., Conclusion: These findings demonstrate that ectopic sprouting of sensory and sympathetic nerve fibers occurs in the painful arthritic joint and may be involved in the generation and maintenance of arthritic pain., (Copyright © 2012 by the American College of Rheumatology.)

Interactions between T cells and noradrenergic pathways were investigated using athymic nude mice as a model. Higher noradrenaline (NA) concentrations and increased density of noradrenergic fibers were found in the spleen and hypothalamus, but not in the kidney, of 21-day-old Foxn1(n) (athymic) mice, compared with Foxn1(n) /Foxn1(+) (heterozygous) littermates. Although no differences in nerve growth factor concentrations were detected, significantly higher brain-derived neurotrophic factor concentrations were found in the spleen and hypothalamus of athymic mice compared with the controls. All of these alterations were abrogated in Foxn1(n) mice reconstituted by thymus transplantation at birth. These results suggest that T lymphocytes or their products can induce (1) a decrease in the number and activity in splenic sympathetic nerve fibers; (2) a decrease in NA content in the hypothalamus, which, in turn, may influence the pituitary-adrenal axis and the descending neural pathways associated with the autonomic nervous system; and (3) changes in neurotrophin concentration in the spleen and hypothalamus., (© 2012 New York Academy of Sciences.)