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Aims: Cardiac sympathetic overactivation is an important trigger of ventricular arrhythmias in patients with chronic heart failure (CHF). Our previous study demonstrated that N-type calcium (Cav2.2) currents in cardiac sympathetic post-ganglionic (CSP) neurons were increased in CHF. This study investigated the contribution of Cav2.2 channels in cardiac sympathetic overactivation and ventricular arrhythmogenesis in CHF., Methods and Results: Rat CHF was induced by surgical ligation of the left coronary artery. Lentiviral Cav2.2-α shRNA or scrambled shRNA was transfected in vivo into stellate ganglia (SG) in CHF rats. Final experiments were performed at 14 weeks after coronary artery ligation. Real-time polymerase chain reaction and western blot data showed that in vivo transfection of Cav2.2-α shRNA reduced the expression of Cav2.2-α mRNA and protein in the SG in CHF rats. Cav2.2-α shRNA also reduced Cav2.2 currents and cell excitability of CSP neurons and attenuated cardiac sympathetic nerve activities (CSNA) in CHF rats. The power spectral analysis of heart rate variability (HRV) further revealed that transfection of Cav2.2-α shRNA in the SG normalized CHF-caused cardiac sympathetic overactivation in conscious rats. Twenty-four-hour continuous telemetry electrocardiogram recording revealed that this Cav2.2-α shRNA not only decreased incidence and duration of ventricular tachycardia/ventricular fibrillation but also improved CHF-induced heterogeneity of ventricular electrical activity in conscious CHF rats. Cav2.2-α shRNA also decreased susceptibility to ventricular arrhythmias in anaesthetized CHF rats. However, Cav2.2-α shRNA failed to improve CHF-induced cardiac contractile dysfunction. Scrambled shRNA did not affect Cav2.2 currents and cell excitability of CSP neurons, CSNA, HRV, and ventricular arrhythmogenesis in CHF rats., Conclusions: Overactivation of Cav2.2 channels in CSP neurons contributes to cardiac sympathetic hyperactivation and ventricular arrhythmogenesis in CHF. This suggests that discovering purely selective and potent small-molecule Cav2.2 channel blockers could be a potential therapeutic strategy to decrease fatal ventricular arrhythmias in CHF., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2020. For permissions, please email: journals.permissions@oup.com.)

To determine the influence of IGF-1 deletion on renal sympathetic nerve activity (RSNA), left ventricular dysfunction, and renal function in deoxycorticosterone acetate (DOCA)-salt hypertensive mice. The DOCA-salt hypertensive mice models were constructed and the experiment was classified into WT (Wild-type mice) +sham, LID (Liver-specific IGF-1 deficient mice) + sham, WT + DOCA, and LID+ DOCA groups. Enzyme-linked immunosorbent assay (ELISA) was used to detect the serum IGF-1 levels in mice. The plasma norepinephrine (NE), urine protein, urea nitrogen and creatinine, as well as RSNA were measured. Echocardiography was performed to assess left ventricular dysfunction, and HE staining to observe the pathological changes in renal tissue of mice. DOCA-salt induction time-dependently increased the systolic blood pressure (SBP) of mice, especially in DOCA-salt LID mice. Besides, the serum IGF-1 levels in WT mice were decreased after DOCA-salt induction. In addition, the plasma NE concentration and NE spillover, urinary protein, urea nitrogen, creatinine and RSNA were remarkably elevated with severe left ventricular dysfunction, but the creatinine clearance was reduced in DOCA-salt mice, and these similar changes were obvious in DOCA-salt mice with IGF-1 deletion. Moreover, the DOCA-salt mice had tubular ectasia, glomerular fibrosis, interstitial cell infiltration, and increased arterial wall thickness, and the DOCA-salt LID mice were more serious in those aspects. Deletion of IGF-1 may lead to enhanced RSNA in DOCA-salt hypertensive mice, thereby further aggravating left ventricular dysfunction and renal damage.

The autonomic nervous system innervates various peripheral tissue functions. Various external stimuli affect autonomic nerve activity, however, there is little information about the involvement of sensory receptors in the responses. The TRPA1 is a calcium-permeable non-selective cation channel which plays a crucial role in the susceptibility to various stimuli. β-Eudesmol, an oxygenated sesquiterpene found in hop essential oil and beer, activates the TRPA1. Intragastric administration of β-eudesmol decreased efferent adrenal sympathetic nerve activity (ASNA) in rats, whereas subcutaneous administration did not. ASNA suppression by β-eudesmol was not observed in TRPA1 knockout rats. The β-eudesmol derived ASNA suppression was partially, but significantly, eliminated by subdiaphragmatic vagotomy in rats, suggesting the afferent vagal nerve from the gastrointestinal tract to the brain is involved in the effect of β-eudesmol on ASNA. Our results indicate that β-eudesmol suppresses ASNA, partly through TRPA1 and the afferent vagus nerve. These findings introduce the physiological significance of the TRPA1 in the control of ASNA., (Copyright © 2018. Published by Elsevier B.V.)

The astrocytic glutamate transporter (GLT1) plays an important role in the maintenance of extracellular glutamate concentration below neurotoxic levels in brain. However, the functional role of GLT1 within the nucleus of the solitary tract (NTS) in the regulation of cardiovascular function remains unclear. We examined the effect of inhibiting GLT1 in the subpostremal NTS on mean arterial pressure (MAP), renal sympathetic nerve activity (RSNA) and heart rate (HR) in anesthetized, artificially ventilated rats. It was found that dihydrokainate (DHK; inhibitor of GLT1, 5 mmol/L, 100 nL) injections into the NTS (n = 6) decreased MAP (50 ± 10 mmHg, mean ± SD), RSNA (89 ± 14%) and HR (37 ± 6 bpm). Pretreatment with kynurenate (KYN; glutamate receptor antagonist, 5 mmol/L, 30 μL) topically applied to the dorsal surface of the brainstem (n = 4) attenuated the responses to NTS injections of DHK (P < 0.01). The effect of DHK on arterial baroreflex function was examined using i.v. infusions of phenylephrine and nitroprusside. DHK reduced baroreflex response range (maximum-minimum) of RSNA by 91 ± 2% and HR by 83 ± 5% (n = 6, P < 0.001). These results indicate that inhibition of GLT1 within the NTS decreases MAP, RSNA, and HR by the activation of ionotropic glutamate receptors. As a result, baroreflex control of RSNA and HR was dramatically attenuated. The astrocytic glutamate transporter in the NTS plays an important role in the maintenance and regulation of cardiovascular function., (© 2018 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.)

A large amount of norepinephrine (NE) released from cardiac sympathetic nerve terminals might accelerate myocardial ischemic injury. Nicorandil (NICO), K ATP channel opener, could attenuate cardiac NE release from the sympathetic nerve terminals during ischemia. The present study aimed to investigate the effects of NICO-induced attenuation of cardiac NE release on myocardial ischemia-reperfusion (I/R) injury in rats, by comparison with the effect of cardiac sympathetic denervation on I/R injury.Cardiac interstitial NE (iNE) concentrations were determined using a microdialysis method. Rats were divided into 3 groups; control, NICO, and denervation groups. Cardiac sympathetic denervation was performed by painting 10% phenol on the left ventricular epicardium 7 days before producing ischemia. The left coronary artery was ligated for 30 minutes and then re-perfused for 120 minutes. NICO (50 μg/kg/minute) was infused intravenously starting 20 minutes before the coronary occlusion to the end of the ligation.The infarct size of the left ventricle was smaller in rats treated with NICO than in control rats (20.2 ± 3.0 versus 50.6 ± 14.7%, P < 0.01). Sympathetic denervation also reduced infarct size (28.5 ± 10.4 %, P < 0.01), which was not significantly different from that in the NICO group. At the end of 30-minute ischemia, iNE increased markedly in control rats (0.1 ± 0.1 to 20.6 ± 5.3 × 10 3 pg/mL), whereas the increase was completely inhibited in denervated rats. NICO markedly attenuated the increase (4.9 ± 3.0 × 10 3 pg/mL, P < 0.01) during ischemia.NICO-induced attenuation of neural NE release during ischemia might, at least in part, contribute to myocardial protection against I/R injury.

Pelvic ganglion (PG) neurons relay sympathetic and parasympathetic signals to the lower urinary tract, comprising the urinary bladder and bladder outlet, and are thus essential for both storage and voiding reflexes. Autonomic transmission is mediated by activation of the nicotinic acetylcholine receptor (nAChR) in PG neurons. Previously, bladder outlet obstruction (BOO), secondary to benign prostatic hyperplasia, was found to increase soma sizes of bladder-projecting PG neurons. To date, however, it remains unknown whether these morphological changes are accompanied by functional plasticity in PG neurons. In the present study, we investigated whether BOO alters acetylcholine receptor (nAChR) transcript expression and current density in bladder PG neurons. Partial ligation of the rat urethra for six weeks induced detrusor overactivity (DO), as observed during cystometrical measurement. In rats exhibiting DO, membrane capacitance of parasympathetic bladder PG neurons was selectively increased. Real-time PCR analysis revealed that BOO enhanced the expression of the transcripts encoding the nAChR α3 and β4 subunits in PG neurons. Notably, BOO significantly increased ACh-evoked current density in parasympathetic bladder PG neurons, whereas no changes were observed in sympathetic bladder and parasympathetic penile PG neurons. In addition, other ligand-gated ionic currents were immune to BOO in bladder PG neurons. Taken together, these data suggest that BOO causes upregulation of nAChR in parasympathetic bladder PG neurons, which in turn may potentiate ganglionic transmission and contribute to the development of DO., (Copyright © 2015 Elsevier B.V. All rights reserved.)

In Parkinson's disease (PD), profound putamen dopamine (DA) depletion reflects denervation and a shift from vesicular sequestration to oxidative deamination of cytoplasmic DA in residual terminals. PD also involves cardiac sympathetic denervation. Whether PD entails myocardial norepinephrine (NE) depletion and a sequestration-deamination shift have been unknown. We measured apical myocardial tissue concentrations of NE, DA, and their neuronal metabolites 3,4-dihydroxyphenylglycol (DHPG), and 3,4-dihydroxyphenylacetic acid (DOPAC) from 23 PD patients and 23 controls and ascertained the extent of myocardial NE depletion in PD. We devised, validated in VMAT2-Lo mice, and applied 5 neurochemical indices of the sequestration-deamination shift-concentration ratios of DOPAC:DA, DA:NE, DHPG:NE, DOPAC:NE, and DHPG:DOPAC-and used a kinetic model to estimate the extent of the vesicular storage defect. The PD group had decreased myocardial NE content (p < 0.0001). The majority of patients (70%) had severe NE depletion (mean 2% of control), and in this subgroup all five indices of a sequestration-deamination shift were increased compared to controls (p < 0.001 for each). Vesicular storage in residual nerves was estimated to be decreased by 84-91% in this subgroup. We conclude that most PD patients have severe myocardial NE depletion, because of both sympathetic denervation and decreased vesicular storage in residual nerves. We found that the majority (70%) of Parkinson's disease (PD) patients have profound (98%) myocardial norepinephrine depletion, because of both cardiac sympathetic denervation and a shift from vesicular sequestration to oxidative deamination of cytoplasmic catecholamines in the residual nerves. This shift may be part of a final common pathogenetic pathway in the loss of catecholaminergic neurons that characterizes PD., (Published 2014. This article is a U.S. Government work and is in the public domain in the USA.)

Developmental expression of Wilms' tumor gene (WT1) and protein is crucial for cell proliferation, apoptosis, differentiation and cytoskeletal architecture regulation. Recently, a potential role of WT1 has been suggested in the development of neural tissue and in neurodegenerative disorders. We have investigated immunohistochemically the developmentally regulated expression and distribution of WT1 in the human fetal peripheral sympathetic nervous system (PSNS) and the gastro-enteric nervous system (GENS) from weeks 8 to 28 gestational age. WT1 expression was restricted to the cytoplasm of sympathetic neuroblasts, while it progressively disappeared with advancing morphologic differentiation of these cells along both ganglionic and chromaffin cell lineages. In adult tissues, both ganglion and chromaffin cells lacked any WT1 expression. These findings show that WT1 is a reliable marker of human sympathetic neuroblasts, which can be used routinely in formalin-fixed, paraffin-embedded tissues. The progressive loss of WT1 in both ganglion and chromaffin cells, suggests its potential repressor role of differentiation in a precise temporal window during the development of the human PSNS and GENS., (Copyright © 2013 Elsevier GmbH. All rights reserved.)

Angiotensin II type 1 receptor (AT1-R) and nuclear factor-kappaB (NF-κB) in the paraventricular nucleus (PVN) play important roles in heart failure (HF); however, the central mechanisms by which AT1-R and NF-κB contribute to sympathoexcitation in HF are yet unclear. In this study, we determined whether interaction between AT1-R and NF-κB in the PVN modulates neurotransmitters and contributes to NAD(P)H oxidase-dependent oxidative stress and sympathoexcitation in HF. Rats were implanted with bilateral PVN cannulae and subjected to coronary artery ligation or sham surgery (SHAM). Subsequently, animals were treated for 4 weeks through bilateral PVN infusion with either vehicle or losartan (LOS, 10 μg/h), an AT1-R antagonist; or pyrrolidine dithiocarbamate (PDTC, 5 μg/h), a NF-κB inhibitor via osmotic minipump. Myocardial infarction (MI) rats had higher levels of glutamate (Glu), norepinephrine (NE) and NF-κB p65 activity, lower levels of gamma-aminobutyric acid (GABA), and more positive neurons for phosphorylated IKKβ and gp91(phox) (a subunit of NAD(P)H oxidase) in the PVN when compared to SHAM rats. MI rats also had higher levels of renal sympathetic nerve activity (RSNA) and plasma proinflammatory cytokines (PICs), NE and epinephrine. PVN infusions of LOS or PDTC attenuated the decreases in GABA and the increases in gp91(phox), NF-κB activity, Glu and NE, in the PVN of HF rats. PVN infusions of LOS or PDTC also attenuated the increases in RSNA and plasma PICs, NE and epinephrine in MI rats. These findings suggest that interaction between AT1 receptor and NF-κB in the PVN contributes to oxidative stress and sympathoexcitation by modulating neurotransmitters in heart failure.

Gastric leptin elicits its cardiovascular and splanchnic sympathoinhibitory responses via a vagal afferent mechanism, however the latter are blunted/abolished in animals fed a medium high fat diet (MHFD). In a diet-induced obesity model we sought to determine whether the renal sympathetic nerve discharge (RSND) and regional vasodilator responses to gastric leptin are also affected by diet and/or obesity. The diet induced obesity model was used in 2 separate studies. After 13 weeks on a MHFD the animals were classified as either obesity prone (OP) or obesity resistant (OR) depending on their weight gain. Control animals were fed a low fat diet for an equivalent period. Arterial pressure (AP) and heart rate (HR) were monitored in isoflurane-anaesthetised, artificially ventilated animals and RSND or regional vascular responses to leptin (15 μg/kg) administered close to the coeliac artery were evaluated. OP rats had higher baseline AP compared to control/OR rats (P<0.05). Close arterial leptin inhibited RSND in control animals but this response was abolished in OR and OP animals (P<0.01 for both). Leptin administration increased renal vascular conductance in control animals but this response was significantly attenuated only in OP animals (P<0.05). The vasodilator response in the superior mesenteric artery was not significantly different in any of the groups (P>0.05). Together these results suggest that, while the renal sympathoinhibitory responses to gastric leptin are affected by diet, the vasodilator responses to leptin in the renal vascular bed are only affected in OP animals. These changes may impact on cardiovascular homeostatic mechanisms in obesity., (Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.)

Sympathetic nerves can regenerate after injury to reinnervate target tissues. Sympathetic regeneration is well documented after chronic cardiac ischemia, so we were surprised that the cardiac infarct remained denervated following ischemia-reperfusion (I-R). We used mice to ask if the lack of sympathetic regeneration into the scar was due to blockade by inhibitory extracellular matrix within the infarct. We found that chondroitin sulfate proteoglycans (CSPGs) were present in the infarct after I-R, but not after chronic ischemia, and that CSPGs caused inhibition of sympathetic axon outgrowth in vitro. Ventricle explants after I-R and chronic ischemia stimulated sympathetic axon outgrowth that was blocked by nerve growth factor antibodies. However, growth in I-R cocultures was asymmetrical, with axons growing toward the heart tissue consistently shorter than axons growing in other directions. Growth toward I-R explants was rescued by adding chondroitinase ABC to the cocultures, suggesting that I-R infarct-derived CSPGs prevented axon extension. Sympathetic ganglia lacking protein tyrosine phosphatase sigma (PTPRS) were not inhibited by CSPGs or I-R explants in vitro, suggesting PTPRS is the major CSPG receptor in sympathetic neurons. To test directly if infarct-derived CSPGs prevented cardiac reinnervation, we performed I-R in ptprs-/- and ptprs+/- mice. Cardiac infarcts in ptprs-/- mice were hyperinnervated, while infarcts in ptprs+/- littermates were denervated, confirming that CSPGs prevent sympathetic reinnervation of the cardiac scar after I-R. This is the first example of CSPGs preventing sympathetic reinnervation of an autonomic target following injury, and may have important consequences for cardiac function and arrhythmia susceptibility after myocardial infarction.

During myocardial ischemia/reperfusion, lipid peroxidation leads to the formation of toxic aldehydes that contribute to ischemic dysfunction. Mitochondrial aldehyde dehydrogenase type 2 (ALDH2) alleviates ischemic heart damage and reperfusion arrhythmias via aldehyde detoxification. Because excessive norepinephrine release in the heart is a pivotal arrhythmogenic mechanism, we hypothesized that neuronal ALDH2 activation might diminish ischemic norepinephrine release. Incubation of cardiac sympathetic nerve endings with acetaldehyde, at concentrations achieved in myocardial ischemia, caused a concentration-dependent increase in norepinephrine release. A major increase in norepinephrine release also occurred when sympathetic nerve endings were incubated in hypoxic conditions. ALDH2 activation substantially reduced acetaldehyde- and hypoxia-induced norepinephrine release, an action prevented by inhibition of ALDH2 or protein kinase Cε (PKCε). Selective activation of G(i/o)-coupled adenosine A(1), A(3), or histamine H(3) receptors markedly inhibited both acetaldehyde- and hypoxia-induced norepinephrine release. These effects were also abolished by PKCε and/or ALDH2 inhibition. Moreover, A(1)-, A(3)-, or H(3)-receptor activation increased ALDH2 activity in a sympathetic neuron model (differentiated PC12 cells stably transfected with H(3) receptors). This action was prevented by the inhibition of PKCε and ALDH2. Our findings suggest the existence in sympathetic neurons of a protective pathway initiated by A(1)-, A(3)-, and H(3)-receptor activation by adenosine and histamine released in close proximity of these terminals. This pathway comprises the sequential activation of PKCε and ALDH2, culminating in aldehyde detoxification and inhibition of hypoxic norepinephrine release. Thus, pharmacological activation of PKCε and ALDH2 in cardiac sympathetic nerves may have significant protective effects by alleviating norepinephrine-induced life-threatening arrhythmias that characterize myocardial ischemia/reperfusion.

Catecholamines (epinephrine and norepinephrine) are synthesised and produced by the adrenal medulla and postganglionic nerve fibres of the sympathetic nervous system. It is known that essential hypertension has a significant neurogenic component, with the rise in blood pressure mediated at least in part by overactivity of the sympathetic nervous system. Moreover, novel therapeutic strategies aimed at reducing sympathetic activity show promise in the treatment of hypertension. This article reviews recent advances within this rapidly changing field, particularly focusing on the role of genetic polymorphisms within key catecholamine biosynthetic enzymes, cofactors, and storage molecules. In addition, mechanisms linking the sympathetic nervous system and other adverse cardiovascular states (obesity, insulin resistance, dyslipidaemia) are discussed, along with speculation as to how recent scientific advances may lead to the emergence of novel antihypertensive treatments.

Our group recently demonstrated that maternal high-fat diet (HFD) consumption is associated with non-alcoholic fatty liver disease, increased apoptosis, and changes in gluconeogenic gene expression and chromatin structure in fetal nonhuman primate (NHP) liver. However, little is known about the long-term effects that a HFD has on hepatic nervous system development in offspring, a system that plays an important role in regulating hepatic metabolism. Utilizing immunohistochemistry and Real-Time PCR, we quantified sympathetic nerve fiber density, apoptosis, inflammation, and other autonomic components in the livers of fetal and one-year old Japanese macaques chronically exposed to a HFD. We found that HFD exposure in-utero and throughout the postnatal period (HFD/HFD), when compared to animals receiving a CTR diet for the same developmental period (CTR/CTR), is associated with a 1.7 fold decrease in periportal sympathetic innervation, a 5 fold decrease in parenchymal sympathetic innervation, and a 2.5 fold increase in hepatic apoptosis in the livers of one-year old male animals. Additionally, we observed an increase in hepatic inflammation and a decrease in a key component of the cholinergic anti-inflammatory pathway in one-year old HFD/HFD offspring. Taken together, these findings reinforce the impact that continuous exposure to a HFD has in the development of long-term hepatic pathologies in offspring and highlights a potential neuroanatomical basis for hepatic metabolic dysfunction.

Current evidence indicates that rises in systemic levels of estrogen create in the uterus an inhibitory environment for sympathetic nerves. However, molecular insights of these changes are far from complete. We evaluated if semaphorin 3F mRNA, a sympathetic nerve repellent, was produced by the rat uterus and if its expression was modulated by estrogen. We also analyzed whether uterine nerves express the semaphorin 3F binding receptor, neuropilin-2. Uterine levels of semaphorin 3F mRNA were measured using real time reverse transcriptase-polymerase chain reaction in prepubertal rat controls and following chronic estrogen treatment. Localization of semaphorin 3F transcripts was determined by in situ hybridization and the expression of neuropilin-2 was assessed by immunohistochemistry. These studies showed that: (1) chronic estrogen treatment led to a 5-fold induction of semaphorin 3F mRNA in the immature uterus; (2) estrogen provoked a tissue-specific induction of semaphorin 3F which was particularly localized in the connective tissue that borders muscle bundles and surrounds intrauterine blood vessels; (3) two major cell-types were recognized in the areas where transcripts were concentrated, fibroblast-like cells and infiltrating eosinophil leukocytes; and (4) some delicate nerve terminal profiles present in the estrogenized uterus were immunoreactive for neuropilin-2. Temporal and spatial expression patterns of semaphorin 3F/neuropilin-2 are consistent with a possible role of this guidance cue in the remodeling of uterine sympathetic innervation by estrogen. Though correlative in its nature, these data support a model whereby semaphorin 3F, in combination with other inhibitory molecules, converts the estrogenized myometrium to an inhospitable environment for sympathetic nerves., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Cardiac sympathetic neurons stimulate heart rate and the force of contraction through release of norepinephrine. Nerve growth factor modulates sympathetic transmission through activation of TrkA and p75NTR. Nerve growth factor plays an important role in post-infarct sympathetic remodeling. We used mice lacking p75NTR to examine the effect of altered nerve growth factor signaling on sympathetic neuropeptide expression, cardiac norepinephrine, and ventricular function after myocardial infarction. Infarct size was similar in wildtype and p75NTR-/- mice after ischemia-reperfusion surgery. Likewise, mRNAs encoding vasoactive intestinal peptide, galanin, and pituitary adenylate cyclase activating peptides were identical in wildtype and p75NTR-/- cardiac sympathetic neurons, as was expression of the TrkA neurotrophin receptor. Norepinephrine content was elevated in the base of the p75NTR-/- ventricle compared to wildtype, but levels were identical below the site of occlusion. Left ventricular pressure, dP/dt(MAX), and dP/dt(MIN) were measured under isoflurane anesthesia 3 and 7 days after surgery. Ventricular pressure decreased significantly 3 days after infarction, and deficits in dP/dt(MAX) were revealed by stimulating beta receptors with dobutamine and release of endogenous norepinephrine with tyramine. dP/dt(MIN) was not altered by genotype or surgical group. Few differences were observed between genotypes 3 days after surgery, in contrast to low pressure and dP/dt(MAX) previously reported in control p75NTR-/- animals. Seven days after surgery ventricular pressure and dP/dt(MAX) were significantly lower in p75NTR-/- hearts compared to WT hearts. Thus, the lack of p75NTR did not enhance cardiac function after myocardial infarction., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Oncocytic metaplasia of the nasopharynx is an exceptional lesion which exact etiopathogenesis, although largely discussed, still remains controversial. The purpose of this paper is to present the epidemiological characteristics and clinical signs of this lesion and to study its pathogenesis and its therapeutic modalities. We report two cases that occurred respectively in a 53- and 60-year-old woman. The first presented with pharyngeal dysesthesia and otalgia. The endoscopic examination revealed an irregularity of the posterior wall of the nasopharynx. The second patient presented with tinnitus, discomfort of the left ear and bilateral hearing loss. Endoscopic exam revealed a bilateral structural abnormality to the eardrum. Microscopy showed focal oncocytic metaplasia of the nasopharynx mucosa in both cases. There was a positive outcare for both patients after excisional biopsy. Oncocytic metaplasia seems to be in relation to the stimulation of sympathic neuropeptidergic nerve fibers which target epithelial, connective, endothelial and lymphoid cells., (Copyright © 2011 Elsevier Masson SAS. All rights reserved.)

Aim: Vascular production of hydrogen peroxide (H(2)O(2)) is implicated in the development and progression of vascular disease. Hydrogen peroxide also promotes neuronal degeneration, which suggests that vascular H(2)O(2) would promote degeneration of perivascular sympathetic nerves. Vascular cells also produce vascular endothelial growth factor (VEGF), which could protect perivascular nerves from the detrimental effects of H(2)O(2) . The aim of this study was to test these hypotheses., Methods: The effects of H(2)O(2) and VEGF on neuronal survival and noradrenaline uptake were studied in cultures of rat post-ganglionic sympathetic neurones. Western analyses of catalase and growth associated protein 43 were performed and reactive oxygen species (ROS) were measured using the fluorescent indicator 5-(and-6)-chloromethyl-2'7'-dichlorodihydrofluorescein diacetate, acetyl ester., Results: Hydrogen peroxide (30 μm) decreased the survival of post-ganglionic sympathetic neurones (57.8 ± 4.8% of control) and decreased noradrenaline uptake into the neurones (14 ± 6% of control). Hyperglycaemia, which is known to increase H(2)O(2), also decreased survival (31.4 ± 12% of control) and noradrenaline uptake (42 ± 18.4% of control). VEGF reduced the effects of H(2)O(2) (94.3 ± 12% of control) and hyperglycaemia (83.5 ± 23.6% of control) on survival. VEGF increased catalase, a primary determinant of intracellular concentrations of H(2)O(2) , and decreased H(2)O(2) -induced increases in ROS., Conclusion: These results indicate that VEGF protects post-ganglionic sympathetic neurones from the detrimental effects of H(2)O(2). Our data suggest that an increase in catalase is the mechanisms underlying this neuroprotection., (© 2011 The Author. Acta Physiologica © 2011 Scandinavian Physiological Society.)

Anatomical and functional studies of the autonomic innervation in the conus arteriosus of the garfishes are lacking. This study reveals that the conus arteriosus of the longnose gar is primarily myocardial in nature, but additionally, large numbers of smooth muscle cells are present in the subendocardium. A well-developed system of adrenergic, cholinergic, substance P (SP) and neuronal nitric oxide synthase (nNOS) positive nerve terminals are found in the wall of the conus arteriosus. Coronary blood vessels running in the adventitia receive a rich supply of nNOS positive nerve fibers, thus suggesting their importance in the nitrergic control of blood flow in the conus arteriosus. The present data show that the patterns of autonomic innervation of the garfish conus arteriosus are more complex than previously appreciated., (Copyright © 2010 Elsevier GmbH. All rights reserved.)

Elevated levels of endogenous estrogens occurring in the course of pathological states of ovaries (follicular cysts, tumors) as well as xenoestrogens may result in hyperestrogenism. In rat, a close relationship between estrogens and sympathetic and sensory neurons supplying the genito-urinary system was reported. Recently, we have shown that long-term estradiol-17β (E(2)) administration affected morphological and immunochemical organization of the sympathetic ovarian neurons in the caudal mesenteric ganglion of adult gilts. In this study, the influence of E(2) overdose on the number and distribution of neurons in the sympathetic chain ganglia (SChG) projecting to the ovary of adult pigs was investigated. The numbers of ovarian dopamine-β-hydroxylase (DβH-), neuropeptide Y (NPY-), somatostatin (SOM-), galanin (GAL-) and estrogen receptors (ERs-) immunoreactive perikarya as well as the density of the intraganglionic nerve fibers containing DβH and/or NPY, SOM, GAL were also determined. On day 3 of the estrous cycle the ovaries of both the control and experimental gilts were injected with retrograde neuronal tracer Fast Blue, to identify the neurons innervating gonads. From day 4 of the estrous cycle to the expected day 20 of the second studied cycle, the experimental gilts were injected with E(2), while the control gilts were receiving oil. After the last E(2)/oil injection, the SChG Th16-S2 were collected and processed for double-labeling immunofluorescence. Injections of E(2): (1) increased the E(2) level in the peripheral blood ~4-5 fold, (2) reduced the total number of Fast Blue-positive postganglionic neurons in the ganglia under investigation, (3) decreased the number of perikarya in the L2-L4 ganglia, (4) reduced the number of perikarya in the ventral, dorsal and central regions of the SChG, (5) decreased the numbers of DβH(+)/NPY(+) and DβH(+)/GAL(+) perikarya and the numbers of DβH(+) but NPY(-), SOM(-) and GAL(-) perikarya in the SChG, (6) decreased the number of perikarya expressing ERs subtype α and β, and (7) decreased the total number of the intraganglionic nerve fibers containing DβH and/or NPY. These results show that long-term E(2) treatment of adult gilts down-regulates the population of both noradrenergic and ERs expressing the SChG ovary supplying neurons. Our findings suggest also that elevated E(2) levels that occur during pathological states may regulate gonadal function(s) by affecting ovary supplying neurons., (Copyright © 2011 Elsevier Inc. All rights reserved.)

In severe congestive heart failure (CHF), sympathetic overactivity correlates with the exacerbation of cardiac performance. To test the hypothesis that the cardiac sympathetic nerve density dramatically changes with the acceleration of circulating norepinephrine (NE) concentration, we investigated the temporal association of nerve growth factor (NGF) expression in the heart and cardiac sympathetic nerve density during the development of CHF in the continuous NE-infused rats. The animals were analyzed at 0-, 1-, 3-, 7-, 14-, and 28-day after implantation of osmotic pump at a rate of 0.05 mg/kg/hr. The cardiac performance was temporally facilitated in NE-exposed rats at 3-day in accordance with the sympathetic hyper-innervation induced by the augmentation of NGF mRNA expression in the heart. In NE-treated rats, left ventricular end-diastolic pressure was significantly increased after 7-day and marked left ventricular hypertrophy and systemic fluid retention were observed at 28-day. CHF-induced sympathetic overactivity further increased plasma NE concentration in NE-treated rats and finally reached to 16.1+/-5.6 ng/ml at 28-day (control level was 0.39+/-0.1 ng/ml, p<0.01). In the decompensated CHF rats at 28-day, the NGF mRNA expression was conspicuously reduced concomitant with the obvious nerve fiber loss confirmed by the immunostaining of nerve axonal marker, PGP9.5 and sympathetic neuron marker, tyrosine hydroxylase. This resulted in the attenuated tissue NE contents and the exacerbating cardiac performance. The cardiac sympathetic fiber loss was also confirmed in NE-exposed DBH (dopamine beta-hydroxylase)-Cre/Floxed-EGFP (enhanced green fluorescent protein) mice with severe CHF, in which sympathetic nerve could be traced by EGFP. Our results suggest that the cardiac sympathetic nerve density is strictly regulated by the NGF expression in the heart and long-exposure of high plasma NE concentration caused myocardial NGF reduction, following sympathetic fiber loss in severe CHF animals., (Copyright 2010 Elsevier B.V. All rights reserved.)

Parkinson's disease and other neurodegenerative disorders associated to changes in alpha-synuclein often result in autonomic dysfunction, most of the time accompanied by abundant expression of this synaptic protein in peripheral autonomic neurons. Given that expression of alpha-synuclein in vascular elements has been previously reported, the present study was undertaken to determine whether alpha-synuclein directly participates in the regulation of vascular responsiveness. We detected by immunohistochemistry perivascular nerve fibers containing alpha-synuclein in the aorta of mice while aortic endothelial cells and muscular fibers themselves did not exhibit detectable levels of this protein. To assess the effect of alpha-synuclein on vascular reactivity, aortic ring preparations obtained from alpha-synuclein-deficient knockout mice and from transgenic mice overexpressing human wild-type alpha-synuclein under the control of the tyrosine hydroxylase-promoter were mounted and equilibrated in organ baths for isometric tension recording. Lack of alpha-synuclein did not modify the relaxant responses to the endothelium-dependent (acetylcholine) and -independent (sodium nitroprusside) vasodilators, but resulted in a greater than normal norepinephrine-induced vasoconstriction along with a lowered response to dopamine, suggesting potential presynaptic changes in dopamine and norepinephrine releases in knockout mice. Overexpression of alpha-synuclein in TH-positive fibers resulted in complex abnormal responses, characterized by lowered acetylcholine-induced relaxation and lowered norepinephrin-induced contraction. Taken together, our data show for the first time that alpha-synuclein is present in sympathetic fibers supplying the murine aorta and provide evidence that changes in alpha-synuclein levels in perivascular fibers play a physiological role in the regulation of vascular function., (2010 Elsevier Ltd. All rights reserved.)

Aims: To examine diadenosine tetraphosphate (Ap(4)A) for its ability to protect the eye from neurodegeneration induced by subconjunctival application of 6-hydroxydopamine (6-OHDA)., Methods: Intraocular neurodegeneration of anterior structures was induced by subconjunctival injections of 6-OHDA. Animals were pre-treated with topical corneal applications of Ap(4)A or saline., Results: 6-OHDA caused miosis, abnormal pupillary light reflexes, a precipitous drop in intraocular pressure and loss of VMAT2-labelled (vesicle monoamine transporter-2, a marker for sympathetic neurones) intraocular neurones. Pre-treatment with Ap(4)A prevented all of these changes from being induced by 6-OHDA, demonstrably preserving the sympathetic innervation of the ciliary processes. This neuroprotective action of Ap(4)A was not shared with the related compounds adenosine, ATP or diadenosine pentaphosphate. P2-receptor antagonists showed that the effects of Ap(4)A were mediated via a P2-receptor., Conclusion: Ap4A is a natural component of tears and aqueous humour, and its neuroprotective effect indicates that one of its physiological roles is to maintain neurones within the eye. Ap(4)A can prevent the degeneration of intraocular nerves, and it is suggested that this compound may provide the basis for a therapeutic intervention aimed at preventing or ameliorating the development of glaucoma associated with neurodegenerative diseases. Furthermore, subconjunctival application of 6-OHDA provides a useful model for studying diseases that cause ocular sympathetic dysautonomia.

Aims: alpha(2)-Adrenoceptors modulate cardiovascular function by vasoconstriction or dilatation, by central inhibition of sympathetic activity, or by feedback inhibition of norepinephrine release from sympathetic neurons. Despite detailed knowledge about subtype-specific functions of alpha(2)-receptors, the relative contributions of sympathetic vs. non-sympathetic receptors involved in these cardiovascular effects have not been identified. The aim of this study was to define the physiological and pharmacological role of alpha(2A)-adrenoceptors in adrenergic vs. non-adrenergic cells at baseline and during sympathetic stress., Methods and Results: Transgenic mice expressing alpha(2A)-adrenoceptors under control of the dopamine beta-hydroxylase (Dbh) promoter were generated and crossed with mice carrying a constitutive deletion in the alpha(2A)- and alpha(2C)-adrenoceptor genes. alpha(2AC)-deficient mice showed increased norepinephrine plasma levels, cardiac hypertrophy, and fibrosis at baseline. Expression of the Dbh-alpha(2A) transgene in sympathetic neurons prevented these effects. In contrast, Dbh-alpha(2A) receptors mediated only a minor part of the bradycardic and hypotensive effects of the alpha(2)-agonist medetomidine. After chronic pressure overload as induced by transverse aortic constriction in mice, the Dbh-alpha(2A) transgene did not reduce norepinephrine spillover, cardiac dysfunction, hypertrophy, or fibrosis. In isolated wild-type atria, alpha(2)-agonist-induced inhibition of [3H]norepinephrine release was significantly desensitized after pressure overload. In primary sympathetic neurons from Dbh-alpha(2A) transgenic mice, norepinephrine and medetomidine induced endocytosis of alpha(2A)-adrenoceptors into neurite processes., Conclusion: alpha(2A)-Adrenoceptors expressed in adrenergic cells are essential feedback inhibitors of sympathetic norepinephrine release to prevent cardiac hypertrophy and fibrosis at baseline. However, these receptors are desensitized by chronic pressure overload which in turn may contribute to the pathogenesis of this condition.

Although generally considered a prototypical movement disorder, Parkinson's disease is commonly associated with a broad-spectrum of non-motor symptoms, including autonomic dysfunctions caused by significant alterations in catecholaminergic neurons of the peripheral sympathetic nervous system. Here we present evidence that alpha-synuclein is highly expressed by sympathetic ganglion neurons throughout embryonic and postnatal life and that it is found in tyrosine hydroxylase-positive sympathetic fibers innervating the heart of adult mice. However, mice deficient in alpha-synuclein do not exhibit any apparent alterations in sympathetic development. Sympathetic neurons isolated from mouse embryos and early postnatal mice are sensitive to the parkinsonian drug MPTP/MPP(+) and intoxication requires entry of the neurotoxin through the noradrenaline transporter. Furthermore, recovery of noradrenaline from cardiac sympathetic fibers is reduced in adult mice treated with MPTP systemically. However, MPP(+)-induced sympathetic neuron loss in vitro or MPTP-induced cardiac noradrenaline depletion in vivo is not modified in mice lacking alpha-synuclein. This is in clear contrast with the observation that dopaminergic neurons of the central nervous system are significantly less vulnerable to MPTP/MPP(+) in the absence of alpha-synuclein, suggesting different actions of this molecule in central and peripheral catecholaminergic neurons., (Copyright 2010 Elsevier Inc. All rights reserved.)

To examine whether feedforward control by central command activates preganglionic adrenal sympathetic nerve activity (AdSNA) and releases catecholamines from the adrenal medulla, we investigated the effects of electrical stimulation of the hypothalamic locomotor region on preganglionic AdSNA and secretion rate of adrenal catecholamines in anaesthetized rats. Pre- or postganglionic AdSNA was verified by temporary sympathetic ganglionic blockade with trimethaphan. Adrenal venous blood was collected every 30 s to determine adrenal catecholamine output and blood flow. Hypothalamic stimulation for 30 s (50 Hz, 100-200 microA) induced rapid activation of preganglionic AdSNA by 83-181% depending on current intensity, which was followed by an immediate increase of 123-233% in adrenal adrenaline output. Hypothalamic stimulation also increased postganglionic AdSNA by 42-113% and renal sympathetic nerve activity by 94-171%. Hypothalamic stimulation induced preferential secretion of adrenal adrenaline compared with noradrenaline, because the ratio of adrenaline to noradrenaline increased greatly during hypothalamic stimulation. As soon as the hypothalamic stimulation was terminated, preganglionic AdSNA returned to the prestimulation level in a few seconds, and the elevated catecholamine output decayed within 30-60 s. Adrenal blood flow and vascular resistance were not affected or slightly decreased by hypothalamic stimulation. Thus, it is likely that feedforward control of catecholamine secretion from the adrenal medulla plays a role in conducting rapid hormonal control of the cardiovascular system at the beginning of exercise.

Aging leads to reduced cellular immunity with consequent increased rates of infectious disease, cancer, and autoimmunity in the elderly. The sympathetic nervous system (SNS) modulates innate and adaptive immunity via innervation of lymphoid organs. In aged Fischer 344 (F344) rats, noradrenergic (NA) nerve density in secondary lymphoid organs declines, which may contribute to immunosenescence with aging. These studies suggest there is SNS involvement in age-induced immune dysregulation. The purpose of this study was to longitudinally characterize age-related change in sympathetic innervation of the spleen and sympathetic activity/tone in male Brown Norway (BN) rats, which live longer and have a strikingly different immune profile than F344 rats, the traditional animal model for aging research. Splenic sympathetic neurotransmission was evaluated between 8 and 32 months of age by assessing (1) NA nerve fiber density, (2) splenic norepinephrine (NE) concentration, and (3) circulating catecholamine levels after decapitation. We report a decline in NA nerve density in splenic white pulp (45%) at 15 months of age compared with 8-month-old (M) rats, which is followed by a much slower rate of decline between 24 and 32 months. Lower splenic NE concentrations between 15 and 32 months of age compared with 8M rats were consistent with morphometric findings. Circulating catecholamine levels after decapitation stress generally dropped with increasing age. These findings suggest there is a sympathetic-to-immune system dysregulation beginning at middle age. Given the unique T-helper-2 bias in BN rats, altered sympathetic-immune communication may be important for understanding the age-related rise in asthma and autoimmunity.

The aim of this study was to determine whether pre-treatment of human skin with the alpha(1)-adrenoceptor antagonist terazosin would block vasoconstrictor responses and axon-reflex vasodilatation to the alpha(1)-adrenoceptor agonist methoxamine. Drugs were administered by iontophoresis into the skin of the forearm of 15 healthy participants, and skin blood flow was monitored with a laser Doppler flow probe at the site of methoxamine iontophoresis (to monitor direct vasoconstrictor responses) or 5-10 mm from the site of methoxamine iontophoresis (to monitor axon-reflex vasodilatation). Experimental sites were pre-treated with terazosin (administered by iontophoresis for 10 min at 200 microA), and the same current intensity was passed through 0.9% saline to control for the nonspecific effects of iontophoresis. Pre-treatment with terazosin blocked vasoconstrictor responses to increasing doses of methoxamine, and also blocked vasodilatation several mm from the site of terazosin and methoxamine administration. These findings support the view that alpha(1)-adrenoceptors play a role in generating axon-reflex vasodilatation, and thus might contribute to local vascular disturbances in acute and chronic inflammation.

The contribution of sympathetic nerves arising from the superior cervical ganglia (SCG) toward the growth and function of cerebral blood vessels is pertinent throughout maturation as well as in response to cardiovascular stress imposed by high-altitude long-term hypoxia (LTH). The function of SCG sympathetic neurons is dependent on intracellular Ca2+ concentration ([Ca2+]i) signaling, which is strongly influenced by a process known as Ca(2+)-induced Ca2+ release (CICR) from the smooth endoplasmic reticulum (SER). In this study, we used the sheep SCG neuronal model to test the hypotheses that maturation decreases CICR and high-altitude LTH depresses CICR in fetal SCG neurons but not in those of the adult. We found that the contribution of CICR to electric field stimulation (EFS)-evoked [Ca2+]i transients was greatest in SCG cells from normoxic fetuses and was abolished by LTH. The decline in CICR was associated with a reduction in sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA) function in fetal SCG cells during LTH, reducing SER Ca2+ levels below the threshold needed for the coupling of Ca2+ influx and CICR. With respect to the maturation from the fetus to adult, the decrease in CICR may reflect both a reduction in the levels of ryanodine receptor isoforms 2 and 3 and SERCA function. In response to LTH and in contrast to the fetus, CICR function in adult SCG cells is maintained and may reflect alterations in other mechanisms that modulate the CICR process. As CICR is instrumental in the function of sympathetic neurons within the cerebrovasculature, the loss of this signaling mechanism in the fetus may have consequences for the adaptation to LTH in terms of fetal susceptibility to vascular insults.

Objective: Tachyarrhythmias are common during epileptic seizures while bradyarrhythmias or asystoles are less frequent. Ictal asystole might be related to epilepsy-induced cardiac sympathetic denervation., Methods: To evaluate cardiac post-ganglionic denervation in epilepsy patients with ictal asystoles we assessed I123-meta-iodobenzylguanidine (MIBG) as a marker of post-ganglionic cardiac norepinephrine-uptake, using single photon emission computed tomography (MIBG-SPECT)., Results: In five of 844 patients with presurgical video-electroencephalography-monitoring, we recorded ictal asystoles during nine of 37 seizures. Asystole patients underwent cardiologic examination (Holter-electrocardiogram, echocardiogram) and cardiac MIBG-SPECT. We compared cardiac MIBG uptake in the asystole patients to the uptake in 18 temporal lobe epilepsy (TLE) patients without bradyarrhythmias and in 14 controls without cardiac or neurological disease. As the cardiological examinations were unremarkable in all subjects, the heart/mediastinum-MIBG-uptake ratios (H/M-ratios) differed significantly between the three groups (P = 0.004). H/M-ratios were lower in asystole TLE patients (mean +/- SD: 1.58 +/- 0.3) than in patients without asystole (1.81 +/- 0.18; P = 0.037) or controls (1.96 +/- 0.16)., Conclusions: Pronounced reduction in cardiac MIBG uptake of asystole patients indicates post-ganglionic cardiac catecholamine disturbance. Impaired sympathetic cardiac innervation limits adjustment and heart rate modulation, and may increase the risk of asystole and ultimately sudden unexpected death in epilepsy (SUDEP).

Inflammation has profound effects on the innervation of affected tissues, including altered neuronal excitability and neurotransmitter release. As Ca(2+) influx through voltage-gated Ca(2+) channels (VGCCs) is a critical determinant of excitation-secretion coupling in nerve terminals, the aim of this study was to characterize the effect of overnight incubation in the inflammatory mediator tumour necrosis factor alpha (TNFalpha; 1 nM) on VGCCs in dissociated neurons from mouse superior mesenteric ganglia (SMG). Voltage-gated Ca(2+) currents (I(Ca)) were measured using the perforated patch clamp technique and the VGCC subtypes present in SMG neurons were estimated based on inhibition by selective VGCC blockers: omega-conotoxin GVIA (300 nM; N-type), nifedipine (10 microM; L-type), and omega-conotoxin MVIIC (300 nM; N-, P/Q-type). We used intracellular Ca(2+) imaging with Fura-2 AM to compare Ca(2+) influx during depolarizations in control and TNFalpha-treated neurons. TNF receptor and VGCC mRNA expression were measured using PCR, and channel alpha subunit (CaV2.2) was localized with immunohistochemistry. Incubation in TNFalpha significantly decreased I(Ca) amplitude and depolarization-induced Ca(2+) influx. The reduction in I(Ca) was limited to omega-conotoxin GVIA-sensitive N-type Ca(2+) channels. Depletion of glial cells by incubation in cytosine arabinoside (5 microM) did not affect I(Ca) inhibition by TNFalpha. Preincubation of neurons with SC-514 (20 microM) or BAY 11-7082 (1 microM), which both inhibit nuclear factor kappaB signalling, prevented the reduction in I(Ca) by TNFalpha. Inhibition of N-type VGCCs following TNFalpha incubation was associated with a decrease in CaV2.2 mRNA and reduced membrane localization of CaV2.2 immunoreactivity. These data suggest that TNFalpha inhibits I(Ca) in SMG neurons and identify a novel role for NF-kappaB in the regulation of neurotransmitter release during inflammatory conditions with elevated circulating TNFalpha, such as Crohn's disease and Guillain-Barré syndrome.

The objective of the present study was to evaluate the correlation between sympathetic nerve activation and inflammatory response in the acute stage of subarachnoid hemorrhage (SAH) in a canine perforating model. SAH was induced by perforation of the basilar artery with the use of a microcatheter via the femoral artery in 20 mongrel dogs. Hemodynamic parameters and intracranial pressure were recorded, and blood sample for C3a, C5b-9, IL-6, IL-8 and noradrenaline kinetic determination were measured at 0, 5, 15, 30, 60, 120, and 180 min after SAH. Noradrenaline (pg/mL) increased abruptly from 104+/-59 to 2010+/-918 at 5 min after SAH. C3a and C5b-9 reached peak values at 15 min and IL-6 and IL-8 reached peak values at 30 min after SAH, respectively. The peak values of C3a and C5b-9 correlated positively with the peak value of noradrenaline (r=0.743 and r=0.753, respectively). The peak values of IL-6 and IL-8 also correlated positively with the peak values of noradrenaline (r=0.603 and r=0.681, respectively).These results suggest that a pronounced activation of the sympathetic nervous system and the inflammatory response occurs in acute stage of SAH. Significant association between the rate of spillover of norepinephrine to plasma and the plasma levels of inflammatory markers indicates that the two processes, sympathetic activation and immune response are quantitatively linked in early stage after SAH. The exact mechanisms underlying this phenomenon deserved further investigations.

Background: The autoantibodies stimulate the beta1-adrenoreceptors on cardiac myocytes similar to norepinephrine, and are associated with reduced cardiac function. Iodine-123 metaiodobenzylguanidine ((123)I-MIBG) is metabolized similarly to norepinephrine. This study was undertaken to investigate the relationship between cardiac stimulation by anti-beta1-adrenoreceptor autoantibodies and myocardial sympathetic nervous activity in patients with chronic heart failure., Methods: We screened for the anti-beta1-adrenoreceptor autoantibodies in 52 patients with chronic heart failure by conducting an enzyme-linked immunosorbent assay, and underwent (123)I-MIBG scintigraphy in 27 of the patients. Anterior planar images of (123)I-MIBG were obtained 15 min and 3 h after the injection. We determined the heart to mediastinum radioactivity ratio (H/M), and calculated the rate of washout of (123)I-MIBG from the heart., Results: Patients with New York Heart Association functional class III or IV had higher levels of anti-beta1-adrenoreceptor autoantibodies than those with class I or II (p<0.01). The autoantibody level was significantly correlated with delayed H/M (r=-0.65, p<0.001) and washout rate (r=0.65, p<0.001). Sixteen patients with a cardiac event showed higher levels of the autoantibodies (p<0.05). Cardiac event-free survival was poorer in patients with the autoantibody levels >10 U/ml than that <10 U/ml (log-rank=12.1, p<0.001)., Conclusion: The anti-beta1-adrenoreceptor autoantibodies are closely associated with cardiac sympathetic nervous activity assessed by (123)I-MIBG and cardiac event in patients with chronic heart failure.

Nerve sprouting in healed myocardial infarction has been associated with increased incidences of ventricular tachyarrhythmia and sudden cardiac death. However, the underlying electrophysiological mechanisms are unclear. To investigate the linkage between nerve sprouting and potassium channel function, we developed a rat model of cardiac sympathetic nerve sprouting by chronic subcutaneous injection of 4-methylcatechol, a potent stimulator of nerve growth factor (NGF) synthesis. Cardiac sympathetic nerves were visualized by immunohistochemical staining. Myocardial necrotic injury was created by focal cold shock across intact diaphragm to mimic infarction. Transient outward current (I(to)) and inward rectifier current (I(K1)) of cardiomyocytes were recorded with the whole-cell patch clamp technique. We found that chronic 4-MC administration 1) increased cardiac NGF level and the density of cardiac sympathetic innervation; 2) decreased the expressions of Kv4.2, Kv channel-interacting protein 2 (KChIP2), Kir2.1, and the current densities of I(to) and I(K1); 3) reduced the phosphorylation of extracellular signal-regulated kinase 1/2 (pERK1/2); and 4) decreased heart rate variability and increased the susceptibility to ventricular fibrillation. Myocardial necrotic injury exerted similar effects as 4-methylcatechol, and 4-methylcatechol plus myocardial necrotic injury intensified the cardiac effects of 4-methylcatechol alone and decreased the phosphoralation of cAMP response element-binding protein (CREB). We conclude that nerve sprouting suppressed the expressions and functions of myocardial I(to) and I(K1) channels and increased the susceptibility to ventricular fibrillation. These effects are associated with decreased phosphorylation of ERK and CREB and reduced expression of KChIP2.

The dorsomedial hypothalamus (DMH) is an essential brain region for the integration of the physiological response to psychological stressors. The cardiovascular components of the response include increases in blood pressure, heart rate and the activity of sympathetic nerves to the kidney, skin, brown adipose tissue, and heart. Neurons in the rostral ventrolateral medulla (RVLM) and in the region of the medullary raphe are important components of the descending pathways that mediate the cardiovascular response to the DMH activation. Activation of 5-hydroxytryptamine 1A (5-HT(1A)) receptors in the brain leads to a suppression of the cardiac and sympathetic vasomotor components of the DMH-evoked response and of the response to acute psychological stress. In this study we showed that intracisternal injection of a low dose (1 microg/kg) of the 5-HT(1A) receptor agonist, 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), significantly reduced the increases in heart rate and renal sympathetic nerve activity evoked by disinhibition of the DMH, but had no effect on these responses when injected intravenously. Subsequent intracisternal administration of the 5-HT(1A) receptor antagonist WAY-100635 restored the DMH-evoked cardiovascular responses to levels observed before 8-OH-DPAT administration. Bilateral microinjections of 8-OH-DPAT (200 pmol on each side) into the RVLM, however, did not significantly affect the cardiovascular response to disinhibition of the DMH. These observations demonstrate that activation of 5-HT(1A) receptors within the lower brainstem, but not in the RVLM, can powerfully suppress the cardiovascular response evoked from the DMH.

To better understand the local neuronal network of the gastro-duodenal junction in ruminants, we identified the components of the enteric nervous system (ENS) innervating the pyloric sphincter (PS) of the lamb abomasum. The neurons were labelled after injecting the tracer Fast Blue (FB) into the wall of the PS, and the phenotype of the FB-labelled neurons was immunohistochemically investigated using antibodies against nitric oxide synthase (NOS), choline acetyltransferase (ChAT), tachykinin (substance P) and tyrosine hydroxylase (TH). The FB-labelled abomasal myenteric plexus (MP) neurons, observed up to 14cm from the PS, were NOS-immunoreactive (IR) (82+/-12%), ChAT-IR (51+/-29%), SP-IR (61+/-33%), and also TH-IR (2%). The descending nitrergic neurons were also SP-IR (64%) and ChAT-IR (21%); the cholinergic descending neurons were SP-IR (3%). The FB-labelled duodenal neurons were located only in the MP, up to 8cm from the sphincter and were ChAT-IR (79+/-16%), SP-IR (32+/-18%), NOS-IR (from 0 to 2%), and also TH-IR (4+/-3%). The cholinergic ascending neurons were also SP-IR (60%) whereas no ChAT-IR cells were NOS-IR. The findings of this research indicate that the sheep PS is innervated by long-projecting neurons of the abomasal and duodenal ENS.

Kv1.3 channels are known to modulate many aspects of neuronal function. We tested the hypothesis that Kv1.3 modulates the function of postganglionic sympathetic neurons. RT-PCR, immunoblot, and immunohistochemical analyses indicated that Kv1.3 channels were expressed in these neurons. Immunohistochemical analyses indicated that Kv1.3 protein was localized to neuronal cell bodies, processes, and nerve fibers at sympathetic neurovascular junctions. Margatoxin (MgTX), a specific inhibitor of Kv1.3, was used to assess the function of the channel. Electrophysiological analyses indicated that MgTX significantly reduced outward currents [P < 0.05; n = 18 (control) and 15 (MgTX)], depolarized resting membrane potential, and decreased the latency to action potential firing [P < 0.05; n = 11 (control) and 13 (MgTX)]. The primary physiological input to postganglionic sympathetic neurons is ACh, which activates nicotinic and muscarinic ACh receptors. MgTX modulated nicotinic ACh receptor agonist-induced norepinephrine release (P < 0.05; n >or= 6), and MgTX-sensitive current was suppressed upon activation of muscarinic ACh receptors with bethanechol (P < 0.05; n = 12). These data indicate that Kv1.3 affects the function of postganglionic sympathetic neurons, which suggests that Kv1.3 influences sympathetic control of cardiovascular function. Our data also indicate that modulation of Kv1.3 is likely to affect sympathetic control of cardiovascular function.

The purpose of the present study was to determine whether thoracic veins may act as ectopic pacemakers and whether nodelike cells and rich sympathetic innervation are present at the ectopic sites. We used a 1,792-electrode mapping system with 1-mm resolution to map ectopic atrial arrhythmias in eight normal dogs during in vivo right and left stellate ganglia (SG) stimulation before and after sinus node crushing. SG stimulation triggered significant elevations of transcardiac norepinephrine levels, sinus tachycardia in all dogs, and atrial tachycardia in two of eight dogs. Sinus node crushing resulted in a slow junctional rhythm (51 +/- 6 beats/min). Subsequent SG stimulation induced 20 episodes of ectopic beats in seven dogs and seven episodes of pulmonary vein tachycardia in three dogs (cycle length 273 +/- 35 ms, duration 16 +/- 4 s). The ectopic beats arose from the pulmonary vein (n = 11), right atrium (n = 5), left atrium (n = 2), and the vein of Marshall (n = 2). There was no difference in arrhythmogenic effects of left vs. right SG stimulation (13/29 vs. 16/29 episodes, P = nonsignificant). There was a greater density of periodic acid Schiff-positive cells (P < 0.05) and sympathetic nerves (P < 0.05) at the ectopic sites compared with other nonectopic atrial sites. We conclude that, in the absence of a sinus node, thoracic veins may function as subsidiary pacemakers under heightened sympathetic tone, becoming the dominant sites of initiation of focal atrial arrhythmias that arise from sites with abundant sympathetic nerves and periodic acid Schiff-positive cells.

The sympathetic nervous system, via postganglionic innervation of blood vessels and the heart, is an important determinant of cardiovascular function. The mechanisms underlying sympathetic innervation of targets are not fully understood. This study tests the hypothesis that target-derived vascular endothelial growth factor (VEGF) promotes sympathetic innervation of blood vessels. Western blot and immunohistochemical analyses indicate that VEGF is produced by vascular cells in arteries and that VEGF receptors are expressed on sympathetic nerve fibers innervating arteries. In vitro, exogenously added VEGF and VEGF produced by vascular smooth muscle cells (VSMCs) in sympathetic neurovascular cocultures inhibited semaphorin 3A (Sema3A)-induced collapse of sympathetic growth cones. In the absence of Sema3A, VEGF and VSMCs also increased growth cone area. These effects were mediated via VEGF receptor 1. In vivo, the neutralization of VEGF inhibited the reinnervation of denervated femoral arteries. These data demonstrate that target-derived VEGF plays a previously unrecognized role in promoting the growth of sympathetic axons.

The role of adrenergic activation in the right coronary (RC) flow response to hypoxia has not been previously delineated, and limited information from left coronary studies is inconsistent. Seven dogs were instrumented with catheters implanted in the aorta and in the right ventricle to measure aortic pressure and right ventricular (RV) pressure, respectively. A flow transducer was placed around the RC artery to measure RC flow. After recovery from surgery, the dogs were exposed to systemic hypoxia in a Plexiglas chamber ventilated with N(2). Percent O(2) in the chamber was monitored, and blood samples and hemodynamic data were collected as chamber O(2) was progressively reduced to approximately 6%. The chamber was then opened, and the dog breathed room air. Phentolamine, 1 mg/kg, and propranolol, 2 mg/kg, were then administered via the RV catheter to achieve adrenergic blockade, and the hypoxia protocol was repeated. During hypoxia, arterial PO(2) progressively fell from 87+/-3 to 25+/-1 mmHg during untreated control condition and from 90+/-4 to 23+/-1 mmHg during adrenergic blockade. In the unblocked condition, hypoxia caused increases in aortic pressure, heart rate, RV pressure, and RV dP/dt(max). After adrenergic blockade, normoxic aortic pressure was reduced; heart rate and RV dP/dt(max) tended to be lower. Aortic pressure rose during hypoxia, but to lesser values than before blockade. Heart rate and RV dP/dt(max) also increased, but only at more severe hypoxia, and these values were less than before blockade. Normoxic flow and hypoxia-induced increases in RC flow and conductance were not altered by blockade. The relationship between RC conductance and RV triple product, an index of RV O(2) demand, was steeper after blockade. These findings indicate that in the normal, unblocked condition, RC flow during hypoxia is restrained by an adrenergic-mediated increase in RC vasomotor tone.

Background: Postganglionic cardiac sympathetic denervation is evident in patients with Parkinson's disease (PD) and iodine-123 metaiodobenzylguanidine ((123)I-MIBG) cardiac scintigraphy has proven to be a useful tool for diagnosis of PD., Objective: To elucidate the factors associated with severity of cardiac sympathetic nerve dysfunction in PD patients., Methods: We investigated 95 PD patients hospitalized in the Department of Neurology at Tottori University Hospital. (123)I-MIBG cardiac scintigraphy was performed on each patient and the early and delayed heart to mediastinum (H/M) ratios and washout rate (WR) of (123)I-MIBG cardiac scintigraphy were calculated. Independent predictive variables for parameters of (123)I-MIBG cardiac scintigraphy were analyzed by multivariate regression analysis., Results: Multivariate regression analysis revealed that the presence of visual hallucinations (VH) and the patient's age at the time of evaluation independently predicted the early or delayed H/M ratio. Analysis of covariance, adjusted for the age of the patients as covariates, revealed that the early and delayed H/M ratios of PD patients with VH but no dementia, as well as PD patients with dementia were significantly lower than the ratios in PD patients with no VH or dementia., Conclusion: Cardiac sympathetic dysfunction may be associated with the presence of VH in PD patients.

The sympathetic nervous system is an important determinant of vascular function. The effects of the sympathetic nervous system are mediated via release of neurotransmitters and neuropeptides from postganglionic sympathetic neurons. The present study tests the hypothesis that vascular smooth muscle cells (VSM) maintain adrenergic neurotransmitter/neuropeptide expression in the postganglionic sympathetic neurons that innervate them. The effects of rat aortic and tail artery VSM (AVSM and TAVSM, respectively) on neuropeptide Y (NPY) and tyrosine hydroxylase (TH) were assessed in cultures of dissociated sympathetic neurons. AVSM decreased TH (39 +/- 12% of control) but did not affect NPY. TAVSM decreased TH (76 +/- 10% of control) but increased NPY (153 +/- 20% of control). VSM expressed leukemia inhibitory factor (LIF) and neurotrophin-3 (NT-3), which are known to modulate NPY and TH expression. Sympathetic neurons innervating blood vessels expressed LIF and NT-3 receptors. Inhibition of LIF inhibited the effect of AVSM on TH. Inhibition of neurotrophin-3 (NT-3) decreased TH and NPY in neurons grown in the presence of TAVSM. These data suggest that vascular-derived LIF decreases TH and vascular-derived NT-3 increases or maintains NPY and TH expression in postganglionic sympathetic neurons. NPY and TH in vascular sympathetic nerves are likely to modulate NPY and/or norepinephrine release from these nerves and are thus likely to affect blood flow and blood pressure. The present studies suggest a novel mechanism whereby VSM would modulate sympathetic control of vascular function.

Neurones in the lumbosacral spinal cord are known to play a significant role in ejaculation. In these same areas neurones containing nitric oxide synthase (NOS) have been described. This raised the question as to whether there is a physiological role for nitrous oxide (NO) in the spinal cord in sexual behavior. We first established immunohistochemical localization of NOS positive neurones in the lumbosacral spinal cord. NOS positive neurones were found in several areas of the lumbosacral cord. Namely the intermediolateral column (IML) at L(1)-L(4) and sacral cord; the dorsal gray commissure above the central canal at L(1)-L(2); the ventral gray area of lamina X below the central canal at L(3)-L(4); the superficial laminae of the dorsal horn at all levels. Secondly, we examined the role of NO in the generation of synchronized bursting activity within the vas deferens nerve and associated penile muscles, typical of sexual responses in the male anesthetized rat. NO modulators were applied directly to the spinal cord at T(13)-L(4) via a catheter placed subdurally (intrathecal) and their effect on the genital responses evoked by systemic administration of p-chloroamphetamine (PCA) or apomorphine (apo) (both 1 mg/kg) was observed. All responses evoked by PCA (n=4) or apo (n=3) were abolished or reduced (n=1) during intrathecal NOS inhibition using N((G)) nitro-L-Arginine methyl ester (l-NAME, 200 mM, 20-microl). NOS inhibition using l-NAME was reversed with simultaneous intrathecal application of the NO substrate l-arginine (100 mM, 20-microl, n=3). The selective neuronal NOS inhibitor 1-(2-trifluoro-methylphenyl) imidazole (100 mM, 20-microl, TRIM) also abolished all responses evoked by PCA (n=3). There was evidence that the responses within the vas deferens nerve (VDN) after PCA or apo were enhanced following NO donation using sodium nitroprusside (SNP, 1 mM, 20-microl). Furthermore, a PCA-like response within the VDN was evoked following intrathecally applied l-glutamic acid (200 mM, 20-microl) in six of 26 animals and also by intrathecal SNP in two of eight animals. In conclusion the results suggest a significant excitatory role for NO in the bursting pattern of synchronized discharge generated in autonomic and somatic outflows from the lumbosacral cord by neurones governing ejaculation.

Background: The ability of a neuron to regenerate functional connections after injury is influenced by both its intrinsic state and also by extrinsic cues in its surroundings. Investigations of the transcriptional changes undergone by neurons during in vivo models of injury and regeneration have revealed many transcripts associated with these processes. Because of the complex milieu of interactions in vivo, these results include not only expression changes directly related to regenerative outgrowth and but also unrelated responses to surrounding cells and signals. In vitro models of neurite outgrowth provide a means to study the intrinsic transcriptional patterns of neurite outgrowth in the absence of extensive extrinsic cues from nearby cells and tissues., Results: We have undertaken a genome-wide study of transcriptional activity in embryonic superior cervical ganglia (SCG) and dorsal root ganglia (DRG) during a time course of neurite outgrowth in vitro. Gene expression observed in these models likely includes both developmental gene expression patterns and regenerative responses to axotomy, which occurs as the result of tissue dissection. Comparison across both models revealed many genes with similar gene expression patterns during neurite outgrowth. These patterns were minimally affected by exposure to the potent inhibitory cue Semaphorin3A, indicating that this extrinsic cue does not exert major effects at the level of nuclear transcription. We also compared our data to several published studies of DRG and SCG gene expression in animal models of regeneration, and found the expression of a large number of genes in common between neurite outgrowth in vitro and regeneration in vivo., Conclusion: Many gene expression changes undergone by SCG and DRG during in vitro outgrowth are shared between these two tissue types and in common with in vivo regeneration models. This suggests that the genes identified in this in vitro study may represent new candidates worthy of further study for potential roles in the therapeutic regrowth of neuronal connections.

Previous studies have demonstrated that histamine (HA) acts as a neurotransmitter in the cardiac sympathetic nervous system of the guinea pig. The aim of the current study was to examine whether HA widely exists in the sympathetic nervous systems of other species and the subcellular localization of HA in sympathetic terminals. An immunofluorescence histochemical multiple-staining technique and anterograde tracing method were employed to visualize the colocalization of HA and norepinephrine (NE) in sympathetic ganglion and nerve fibers in different species. Pre-embedding immunoelectron microscopy was used to observe the subcellular distribution of HA in sympathetic nerve terminals. Under the confocal microscope, coexistence of NE and HA was displayed in the superior cervical ganglion and celiac ganglion neurons of the mouse and dog as well as in the vas deferens, mesenteric artery axon, and varicosities of the mouse and guinea pig. Furthermore, colocalization of NE and HA in cardiac sympathetic axons and varicosities was labeled by biotinylated dextranamine injected into the superior cervical ganglion of the guinea pig. By electron microscopy, HA-like high-density immunoreactive products were seen in the small vesicles of the guinea pig vas deferens. These results provide direct cellular and subcellular morphological evidence for the colocalization of HA and NE in sympathetic ganglion and nerve fibers, and support that HA is classified as a neurotransmitter in sympathetic neurons.

Calcitonin gene-related peptide (CGRP) and adrenomedullin (AM) are potent vasodilators and exert positive chronotropic and inotropic effects on the heart. Receptors for CGRP and AM are calcitonin receptor-like receptor (CLR)/receptor-activity-modifying protein (RAMP) 1 and CLR/RAMP2 heterodimers, respectively. The present study was designed to delineate distinct cardiovascular effects of CGRP and AM. Thus a V5-tagged rat CLR was expressed in transgenic mice in the vascular musculature, a recognized target of CGRP. Interestingly, basal arterial pressure and heart rate were indistinguishable in transgenic mice and in control littermates. Moreover, intravenous injection of 2 nmol/kg CGRP, unlike 2 nmol/kg AM, decreased arterial pressure equally by 18 +/- 5 mmHg in transgenic and control animals. But the concomitant increase in heart rate evoked by CGRP was 3.7 times higher in transgenic mice than in control animals. The effects of CGRP in transgenic and control mice, different from a decrease in arterial pressure in response to 20 nmol/kg AM, were suppressed by 2 micromol/kg of the CGRP antagonist CGRP(8-37). Propranolol, in contrast to hexamethonium, blocked the CGRP-evoked increase in heart rate in both transgenic and control animals. This was consistent with the immunohistochemical localization of the V5-tagged CLR in the superior cervical ganglion of transgenic mice. In conclusion, hypotension evoked by CGRP in transgenic and control mice was comparable and CGRP was more potent than AM. Unexpectedly, the CLR/RAMP CGRP receptor overexpressed in postganglionic sympathetic neurons of transgenic mice enhanced the positive chronotropic action of systemic CGRP.

Simultaneous electrophysiology and confocal microscopy were used to investigate purinergic neurotransmission at single smooth muscle cells (SMCs) in mouse isolated vas deferens, and to explore the relationship between two high-resolution P2X-receptor-mediated measures of per pulse ATP release: transient peaks in the first time derivative of the rising phase of excitatory junction potentials (EJPs) recorded in single SMCs ('discrete events'; DEs) and neuroeffector Ca(2+) transients (NCTs) in the impaled SMCs. This study shows that discrete events represent neurotransmitter release onto the impaled cell. First, the median amplitude of the first derivative of the EJP was larger when there was a coincident NCT in the impaled cell, compared with instances when no coincident NCT occurred. Second, the time-to-peak amplitude of the first derivative was shorter if there was a coincident NCT in the impaled cell, compared with when no coincident NCT was observed within the field. Surprisingly, first derivative amplitude increased with the distance (of the corresponding NCT) from the microelectrode. The microelectrode did not locally inhibit the functional quantal size as there was no effect of distance on the normalized NCT amplitude. When the significant effect of distance (between the microelectrode and NCTs) on the first derivative amplitude was removed, there was no correlation between the unstandardized residual (of distance vs. first derivative amplitude) and NCT amplitude. The absence of a correlation between DE and NCT amplitudes suggests that the NCT amplitude is a poor measure of quantal size. The usefulness of NCTs hence lies primarily in locating neurotransmitter release and measuring changes in local release probability.

This work aimed to investigate the molecular mechanisms involved in the interaction of alpha2-adrenoceptors and adenosine A2A-receptor-mediated facilitation of noradrenaline release in rat tail artery, namely the type of G-protein involved in this effect and the step or steps where the signalling cascades triggered by alpha2-adrenoceptors and A2A-receptors interact. The selective adenosine A2A-receptor agonist 2-p-(2-carboxy ethyl) phenethylamino-5'-N-ethylcarboxamidoadenosine (CGS 21680; 100 nM) enhanced tritium overflow evoked by trains of 100 pulses at 5 Hz. This effect was abolished by the selective adenosine A2A-receptor antagonist 5-amino-7-(2-phenyl ethyl)-2-(2-furyl)-pyrazolo-[4,3-e]-1,2,4-triazolo [1,5-c]pyrimidine (SCH 58261; 20 nM) and by yohimbine (1 microM). CGS 21680-mediated effects were also abolished by drugs that disrupted G(i/o)-protein coupling with receptors, PTX (2 microg/ml) or NEM (40 microM), by the anti-G(salpha) peptide (2 microg/ml) anti-G(betagamma) peptide (10 microg/ml) indicating coupling of A2A-receptors to G(salpha) and suggesting a crucial role for G(betagamma) subunits in the A(2A)-receptor-mediated enhancement of tritium overflow. Furthermore, phorbol 12-myristate 13-acetate (PMA; 1 microM) or forskolin (1 microM), direct activators of protein kinase C and of adenylyl cyclase, respectively, also enhanced tritium overflow. In addition, PMA-mediated effects were not observed in the presence of either yohimbine or PTX. Results indicate that facilitatory adenosine A2A-receptors couple to G(salpha) subunits which is essential, but not sufficient, for the release facilitation to occur, requiring the involvement of G(i/o)-protein coupling (it disappears after disruption of G(i/o)-protein coupling, PTX or NEM) and/or G(betagamma) subunits (anti-G(betagamma)). We propose a mechanism for the interaction in study suggesting group 2 AC isoforms as a plausible candidate for the interaction site, as these isoforms can integrate inputs from G(salpha) subunits (released after adenosine A2A-receptor activation; prime-activation), G(betagamma) subunits (released after activation of G(i/o)-protein coupled receptors) which can directly synergistically stimulate the prime-activated AC or indirectly via G(betagamma) activation of the PLC-PKC pathway.