Search

The distribution of Fos expression in catecholaminergic neurons with immunoreactivity for dopamine β-hydroxylase (DBH) of the ventrolateral medulla was compared between rats exposed to hypoxia (10 % O 2), hypercapnia (8 % CO 2), and hypercapnic hypoxia (8 % CO 2 and 10 % O 2) for 2 h. Among the experimental groups, hypoxia-exposed rats had more Fos/DBH double-immunoreactive neurons than the control group (20 % O 2) in the rostral area of the ventrolateral medulla, specifically in the range of + 150 μm to + 2,400 μm from the caudal end of the facial nerve nucleus. On the other hand, Fos/DBH double-immunoreactive neurons were scarcely observed in the ventrolateral medullary region of hypercapnia-exposed rats. The number of double-immunoreactive neurons in hypercapnic hypoxia-exposed rats was comparable to that in the control group. The present results suggest that adrenergic C1 neurons are specifically activated by hypoxia and are involved in the regulation of respiratory and circulatory functions. [ABSTRACT FROM AUTHOR]

The commonly used lipopolysaccharide (LPS)-induced depression models often evaluate depression-like behaviors in the acute phase after a single intraperitoneal injection of LPS, and are not suitable for examining long-term depression-like behaviors. To overcome this limitation, we developed a mice LPS model for elucidating the long-term pathophysiology of depression. Using the tail-suspension test, we show that a single intraperitoneal injection of a high dose (1.66 mg/kg) of LPS prolonged depression-like behavior to 14 days after LPS administration unlike 4 days after administration for the most commonly used LPS dose (0.83 mg/kg). Upon high-LPS dose administration, TNF-α levels in the cerebrospinal fluid were increased only on the first day after administration. Moreover, LPS-induced depression-like behavior on day 10 after LPS administration was prevented by imipramine or minocycline. Immunohistochemical analysis revealed reduced neurogenesis in the hippocampal dentate gyrus of LPS-treated mice on day 10 of LPS administration. The LPS model, in which a single intraperitoneal administration of LPS at a dose double of the standard dose used currently, exhibits depression-like behavior via reduced neurogenesis mediated by neuroinflammation, and should be useful for elucidating the long-term pathophysiology of depression and for studying antidepressant drugs. [ABSTRACT FROM AUTHOR]

[Display omitted] Extracranial waste transport from the brain interstitial fluid to the deep cervical lymph node (dCLN) is not extensively understood. The present study aims to show the cranial nerves that have a role in the transport of brain lymphatics vessels (LVs), their localization, diameter, and number using podoplanin (PDPN) and CD31 immunohistochemistry (IHC) and Western blotting. Cranial nerve samples from 6 human cases (3 cadavers, and 3 autopsies) were evaluated for IHC and 3 autopsies for Western blotting. The IHC staining showed LVs along the optic, olfactory, oculomotor, trigeminal, facial, glossopharyngeal, accessory, and vagus nerves. However, no LVs present along the trochlear, abducens, vestibulocochlear, and hypoglossal nerves. The LVs were predominantly localized at the endoneurium of the cranial nerve that has motor components, and LVs in the cranial nerves that had sensory components were present in all 3 layers. The number of LVs accompanying the olfactory, optic, and trigeminal nerves was classified as numerous; oculomotor, glossopharyngeal, vagus, and accessory was moderate; and facial nerves was few. The largest diameter of LVs was in the epineurium and the smallest one was in the endoneurium. The majority of Western blotting results correlated with the IHC. The present findings suggest that specific cranial nerves with variable quantities provide a pathway for the transport of wastes from the brain to dCLN. Thus, the knowledge of the transport of brain lymphatics along cranial nerves may help understand the pathophysiology of various neurological diseases. [ABSTRACT FROM AUTHOR]

Dementia with Lewy Bodies (DLB) is a common neurodegenerative disorder of the aging population characterized by α-synuclein accumulation in cortical and subcortical regions. Although neuropathology in advanced age has been investigated in dementias such as Alzheimer Disease (AD), severity of the neuropathology in the oldest old with DLB remains uncharacterized. For this purpose we compared characteristics of DLB cases divided into three age groups 70-79, 80-89 and ≥ 90 years (oldest old). Neuropathological indicators and levels of synaptophysin were assessed and correlated with clinical measurements of cognition and dementia severity. These studies showed that frequency and severity of DLB was lower in 80-89 and ≥ 90 year cases compared to 70-79 year old group but cognitive impairment did not vary with age. The extent of AD neuropathology correlated with dementia severity only in the 70-79 year group, while synaptophysin immunoreactivity more strongly associated with dementia severity in the older age group in both DLB and AD. Taken together these results suggest that the oldest old with DLB might represent a distinct group.

• Our antibody recognizes linear polyubiquitin chain (L-Ub). • We examined the hippocampus of patients with Alzheimer's disease. • A subset of abnormally accumulated tau proteins was L-Ub immunopositive. • L-Ub is added to a subset of lys48-linked polyubiquitinated tau aggregation. Characteristic neuropathological structures observed in Alzheimer's disease, such as neurofibrillary tangles and dystrophic neurites of senile plaques, are universally ubiquitinated. Eight linkage types of polyubiquitin chains are known, and each type of chain exerts different intracellular action. Among them, linear polyubiquitin chain was recently reported to be associated with the pathomechanism of neuronal cell death. We therefore generated a novel antibody that specifically recognizes linear polyubiquitin chain. We immunohistochemically examined the brains of patients with Alzheimer's disease. A subset of neurofibrillary tangles, dystrophic neurites of senile plaques, and neuropil threads were evident to be immunopositive for linear polyubiquitin chains, but their number was fewer than those recognized by the antibody against K48-linked polyubiquitin chains. Double immunofluorescence investigation showed that in certain neurofibrillary tangles, a part of K48-linked polyubiquitin-immunopositive structures were immunolabeled for linear polyubiquitin chains. Our results imply that linear polyubiquitination follows K48-linked polyubiquitination in abnormally accumulated tau proteins in Alzheimer's disease, and imply involvement in its neurodegeneration. [ABSTRACT FROM AUTHOR]

Highlights • trkA is expressed in trigeminal senosry neurons of all sizes. • trkA is expressed in all types of trigeminal primary sensory fibers. • about 35% of all trkA + fibers were unmyelinated. • about 35% of trkA + neurons coexpress SP or CGRP. • about 11% of trkA + neurons coexpress parvalbumin. Abstract Tropomyosin receptor kinase A (trkA), a high affinity receptor for nerve growth factor (NGF), has been implicated in neuronal survival, neurite outgrowth and inflammatory pain. So far, the characterization of the primary sensory neurons that express trkA, and are thus potentially affected by NGF, has remained incomplete. The goal of this study was to investigate the trkA-expressing neurons and fibers in the rat trigeminal ganglion and its sensory root using light- and electron-microscopic immunohistochemistry and quantitative analysis. TrkA-immunopositive (+) trigeminal neurons varied from small to large. Double immunofluorescent staining showed that about 28%, 33% and 3% of the trkA(+) neurons coexpressed SP, CGRP and IB4, respectively. About 11% of the trkA(+) neurons also coexpressed parvalbumin. Electron microscopy revealed that trkA was expressed in all types of fibers: While the large majority of the trkA(+) fibers were unmyelinated (35.3%) and small myelinated (<20 μm2 in cross-sectional area; 45.5%), a still considerable fraction (19.2%) was large myelinated. These findings indicate that all types of trigeminal neurons (ones with unmyelinated, small myelinated or large myelinated fibers) may be regulated by NGF/trkA signaling. [ABSTRACT FROM AUTHOR]

• Hypothalamic TRPM8-expressing neurons are GABAergic. • TRPM8-expressing neurons of the LS are calbindin and calretinin positive. • TRPM8-expressing neurons of the ROA are EP3 and neurotensin positive. Transient receptor potential melastatin 8 (TRPM8) is a menthol receptor that detects cold temperatures and influences behaviors and autonomic functions under cold stimuli. Despite the well-documented peripheral roles of TRPM8, the evaluation of its central functions is still of great interest. The present study clarifies the nature of a subpopulation of TRPM8-expressing neurons in the adult mice. Combined in situ hybridization and immunohistochemistry revealed that TRPM8-expressing neurons are exclusively positive for glutamate decarboxylase 67 mRNA signals in the lateral septal nucleus (LS) and preoptic area (POA) but produced no positive signal for vesicular glutamate transporter 2. Double labeling immunohistochemistry showed the colocalization of TRPM8 with vesicular GABA transporter at axonal terminals. Immunohistochemistry further revealed that TRPM8-expressing neurons frequently expressed calbindin and calretinin in the LS, but not in the POA. TRPM8-expressing neurons in the POA expressed a prostaglandin E2 receptor, EP3, and neurotensin , whereas expression in the LS was minimal. These results indicate that hypothalamic TRPM8-expressing neurons are inhibitory GABAergic, while the expression profile of calcium-binding proteins, neurotensin , and EP3 differs between the POA and LS [ABSTRACT FROM AUTHOR]

Highlights • Adenosine receptors up-regulate during light-induced retinal degeneration. • A1 receptor increases in the moment of maximal oxidative stress. • A2a receptor peaks in the moment of maximal apoptosis. • A3 receptor mRNA increases later at the moment of maximal tissue damage. • Two potential therapeutic windows may be described in the model of LIRD. Abstract The modulation of adenosine receptors, A1 (A1R) and A2A (A2AR), is neuroprotective in different models of retinal injury. In order to understand the processes underlying retinal degeneration, we studied the expression of adenosine receptors in the retinas of control and continuously illuminated (CI) rats by qRT-PCR, Western blot (WB) and immunohistochemistry (IHC). Significant increases of A1R, A2AR, and A2BR mRNAs at 1, 5, and 7 days of CI (P < 0.0001) were observed by qRT-PCR. Also, a significant increase of A3R mRNA was detected after 5 and 7 days of CI. WB studies showed a significant rise of A1R on day 1 of CI and on days 5 and 7 (P < 0.0001), while A2AR increase was seen from 2 days of CI on (P < 0.001). After 1 day of CI, A1R immunoreactivity (A1R-IR) increased in ganglion cell layer, inner nuclear layer, and in both the outer and inner plexiform layers. After 2 days of CI, the A1R-IR went back to control levels. After 5 days of CI, a second rise in A1R, which persisted until 7 days of CI, was measured (P < 0.0001). A significant rise of A2aR immunoreactivity was also observed at day 2 of CI at GCL and INL and subsided at days 5 and 7 (P < 0.0001). The observed up-regulation of A1R after 1 day of CI, corresponds with the peak of oxidative stress; while the rise of A2aR at day 2 of CI, coincides with the massive apoptosis of photoreceptors. We postulate that an early modulation of adenosine receptors could delay or prevent the degeneration of photoreceptors. [ABSTRACT FROM AUTHOR]

Highlights • The cerebellum participatesin olfactory processing. • Olfactory stimulation with different odor activates the lobules 6a and 7 of the cerebellum. • Successive trials of sexual experience increase the response evoked by the three types of olfactory stimuli. • In sexually expert male rats, exposure to receptive female (RF) stimulus resulted in highest amplitudes. • The amplitude of multiunit activity increases in the control group during the learning of sexual behavior. Abstract The cerebellum is a structure of the central nervous system which has been previously studied with different techniques and animal models and even humans, so it is associated with multiple functions such as cognition, memory, emotional processing, balance, control of movement, among others. Its relationship with sensory systems has already been explored, however, the role it plays in olfactory processing in the cerebellum is unclear. Several hypotheses have been proposed from work done in humans and animal models with neuroimaging and immunohistochemical techniques. Everything seems to indicate that the cerebellar function is of vital importance for the olfactory perception, being able to be controlling not only the olfactory aspect, but also the olfactory processing. In this study we analyzed the multiunit activity in the granular layer of the cerebellar vermis during olfactory stimulation: a session being sexually naive and during four sessions of sexual behavior learning. The amplitude was compared between male naive and sexual experts, as well as between olfactory stimuli. The amplitude of the sexually experienced rats showed the highest values compared to naive ones. Odor of receptive female causes the greatest amplitudes, however, in the control group the amplitude increased when they were sexually experts. The motor, sensory and associative learning generated by the acquisition of sexual experience modifies the activation pattern in the cerebellum by presenting neutral odors or associated with a reward. [ABSTRACT FROM AUTHOR]

Highlights • c-Fos expression in the MPNc increases after ejaculation in male rats. • c-Fos expression in non-calbindin MPNc neurons decreases with sexual experience. • The MPNc may change functionally with sexual experience. Abstract The medial preoptic area (MPN) plays an important role in the control of male sexual behavior. In rats, the central part of the MPN (MPNc) is sexually dimorphic and contains a sexually dimorphic nucleus composed of neurons expressing calbindin-D28 K (CALB-SDN). Although the functions of the MPNc are not well understood, surgical destruction of the MPNc adversely affects the performance of sexual behavior in sexually naive males, but not in sexually experienced males, supporting the notion that the MPNc changes functionally with sexual experience. In this study, we aimed to determine the effects of sexual experience on the neuronal activity of the MPNc and CALB-SDN. Sexual behavior in sexually inexperienced males that had no experience of ejaculation, and experienced males that had ejaculated once was observed. After they displayed sexual behavior, the brains were sampled, and immunohistochemical analysis of c-Fos, a neuronal activity marker, in the MPNc and CALB-SDN was performed. The numbers of c-Fos-immunopositive cells with or without calbindin-D28K-immunoreactivity increased significantly in the MPNc and CALB-SDN following ejaculation in both sexually inexperienced and experienced males, although the numbers did not change significantly with exposure to estrous female odors, the first mount, and the first intromission before and after the first ejaculation. We further found that the number of c-Fos-immunopositive and calbindin-D28K-immunonegative cells in the MPNc, but not in the CALB-SDN, was significantly smaller in sexually experienced males than in sexually inexperienced males. These results suggest that a population of MPNc neurons, which is located outside the CALB-SDN and do not express calbindin-D28 K, are activated during the first copulation and then silent after acquisition of sexual experience. [ABSTRACT FROM AUTHOR]

Highlights • Blood glucose was abnormal, glucose tolerance was impaired in injury-induced mice. • Pancreatic-islet microvascular vasomotion was impaired following injury. • VEGF-A level was correlated with the functional parameters of vasomotion. Abstract Patients with spinal cord injury (SCI) have an increased risk for developing type 2 diabetes. It is unknown whether the pancreatic-islet microvascular vasomotion is involved. We used female C57BL/6 mice and a 100-kilodyne T10 Infinite Horizons contusion SCI (or T10 laminectomy) to detect blood glucose and pancreatic-islet microvascular vasomotion. Blood glucose obtained from tail vein was detected using one Touch UltraEasy glucometer. Glucose tolerance test was performed by d -glucose administration intraperitoneally. Functional status of pancreatic-islet microvascular vasomotion was determined by laser Doppler monitoring. Expressions of insulin and glucagon were determined by immunohistochemistry. Expression of VEGF-A was determined by immunohistochemistry and Western blotting. Our result demonstrated that blood glucose was significantly increased at 4 h postinjury compared to that in sham group, with continuous higher blood glucose until 4 days postinjury (p < 0.05). SCI mice at day 7 and day 14 had significantly impaired glucose tolerance following glucose administration (p < 0.01). Average blood perfusion, amplitude, frequency, and relative velocity of vasomotion were significantly lower at 6 h postinjury than those in the sham group (p < 0.05), which were gradually upregulated over time. The expression of insulin was decreased, while the expression of glucagon was increased at 6 h postinjury. Similarly, the expression of VEGF-A was significantly decreased at 6 h postinjury, compared to that in sham group (p < 0.05), with slight increases by 14 days postinjury. Our study suggests that the functional status of pancreatic-islet microvascular vasomotion is impaired after injury, which may have implications for developing effective therapeutic interventions for SCI. [ABSTRACT FROM AUTHOR]

Introduction The lateral geniculate nucleus (LGN) is the major relay center of the visual pathway in humans. There are few quantitative data on the morphology of LGN in prenatal infants. In this study, using serial brain sections, the author investigated the morphology of this nucleus during the second half of fetal period. Material and methods Eleven human brains were obtained at routine autopsy from preterm infants aged 20–39 postmenstrual weeks. After fixation, the brain was embedded en bloc in celloidin and cut serially at 30 μm in the horizontal plane. The sections were stained at regular intervals using the Klüver–Barrera method. Results At 20–21 weeks, the long axis of LGN declined obliquely from the vertical to horizontal plane, while a deep groove was noted on the ventro-lateral surface of the superior half. At this time, an arcuate cell-sparse zone appeared in the dorso-medial region, indicating the beginning of lamination. From 25 weeks onwards, the magnocellular and parvocellular layers were distinguishable, and the characteristic six-layered structure was recognized. The magnocellular layer covered most of the dorsal surface, and parts of the medial, lateral, and inferior surfaces but not the ventral and superior surfaces. Nuclear volume increased exponentially with age during 20–39 weeks, while the mean neuronal profile area increased linearly during 25–39 weeks. Conclusion Human LGN develops a deep groove on the ventro-lateral surface at around mid-gestation, when the initial lamination is recognized in the prospective magnocellular layer. Thereafter, the nuclear volume increases with age in an exponential function. [ABSTRACT FROM AUTHOR]

Ischemic postconditioning (IPostC) protects against stroke, but few have studied the pathophysiological mechanisms of its long-term protective effects. Here, we investigated whether the mTOR pathway is involved in the long-term protective effects of IPostC. Stroke was induced in rats by distal middle cerebral artery occlusion (dMCAo) combined with 30 min of bilateral common carotid artery (CCA) occlusion, and IPostC was induced after the CCA release. Injury size and behavioral tests were measured up to 3 weeks post stroke. We used rapamycin and mTOR shRNA lentiviral vectors to inhibit mTOR activities, while S6K1 viral vectors, a main downstream mTOR gene, were used to promote mTOR activities. We found that rapamycin administration abolished the long-term protective effects of IPostC. In addition, IPostC promoted the presynaptic growth associated protein 43 (GAP-43) and the postsynaptic protein 95 (PSD-95) levels at 1 week post-stroke, which were reduced by rapamycin. Furthermore, rapamycin reduced phosphorylated mTOR (p-mTOR) protein levels measured at 3 weeks after stroke. These results were confirmed by mTOR shRNA transfection. Moreover, we found that injection of S6K1 viral vectors promoted GAP-43 and PSD-95 protein levels. We conclude that mTOR may play a crucial, protective role in brain damage after stroke and contribute to the protective effects of IPostC. [ABSTRACT FROM AUTHOR]

Genetically modified mouse strains that express Cre-recombinase in specific neuronal sub-populations have become widely used tools for investigating neuronal function. The Ntsr1-Cre GN220 mouse expresses this enzyme in corticothalamic neurons in layer 6 of cerebral cortex. We observed that about 7% of Cre-expressing cells in the primary visual cortex are found within the white matter bordering layer 6. By using the immunohistochemical marker for layer 6 neurons, Forkhead box protein 2 (FoxP2), and fluorescently conjugated latex beads injected into the dorsal lateral geniculate nucleus, we show that about half of these cells are similar to and could belong to the layer 6 corticothalamic neuron population. The other half seems to be a distinct white matter (WM) neuron sub-population that we estimate to constitute 2–4% of the total cortical Cre-expressing population. Staining for the neuronal marker Neuronal nuclei (NeuN) revealed that about 15–40% of WM neurons are Cre-expressing. Thus, the potential contribution from WM neurons needs to be considered when interpreting the results from experiments using the Ntsr1-Cre GN220 mouse for investigating corticothalamic neuronal function. [ABSTRACT FROM AUTHOR]

It was accepted for a long time that in mammals there is only retinofugal neuronal connection between the eye and the pineal body (PB). In our previous paper we described that nerve cells were present in hamster PB and these neurons could establish a reverse connection with the retina through a transsynaptic pathway. In adult albino rats neuronal perikarya were not found. In this present experiment it was examined whether the lack of these nerve cells in the PB of adult rats is the result of an apoptotic phenomenon or the lack of migration during the fetal period. Green fluorescence protein expressing pseudorabies virus, spreading only in retrograde direction, was injected into the vitreous body of rats at various postnatal ages. Virus labeled cell bodies were not observed in the PB of adult rats; however, labeling with gradually decreasing number of cells was present in animals aged 3–6, 13–14, 20, 35 and 41 postnatal days. Injection of virus, spreading in anterograde direction (expressing red fluorescence protein), into the PB of young prepubertal animals resulted in labeling in the retina. This observation indicates that the pinealo-retinal connection in prepubertal period is active. Immunostaining revealed that some of the labeled neuronal perikarya showed activated caspase-3 (an apoptotic marker) immunoreactivity. Our results clearly show that the neurons migrate to the PB and later, during the prepubertal period, they disappear. Caspase-3 immnoreactivity indicates that these cells die off by apoptosis. [ABSTRACT FROM AUTHOR]

Recent reports have characterized functional lymphatic vessels, which drain both fluid and immune cells from the CSF to the deep cervical lymph nodes, lining the dural sinuses in mice. If conserved in the human brain these vessels could have profound implications for neuroinflammatory and neurodegenerative diseases. We provide evidence of the presence of lymphatic vessels in human dura obtained at autopsy, at the level of the superior sagittal sinus, in 4 individuals. Immunohistochemistry for the lymphatic vessel endothelial cell marker podoplanin revealed the widespread presence of multiple structures with a distinct lumen distributed throughout the superior sagittal sinus. These vessels provide a putative infrastructure for drainage of macromolecules from the brain parenchyma and represent an exciting avenue of exploration for involvement in the pathogenesis of neurodegenerative proteinopathies including Parkinson’s disease. [ABSTRACT FROM AUTHOR]

Neuropathic pain (NP) is present in 40-to-50% of spinal cord injured patients. It tends to chronicity and correlates with lower quality-of-life. Moreover, the role of NP in the eventual exacerbation of anxiety- and depression-like behaviours during its development and chronification in genetically susceptible individuals remains unclear. Thus, although solely few animal models are available, new specific models are needed to complete the array of chances to assay new therapeutic strategies with the aim of treating chronic NT and its associated mood disorders. The present study was conceived to evaluate hyperalgesic responses and anxiety- and depression-like behaviours after graded photochemical spinal cord injury (SCI) up to chronic phase. BALB/c strain was used: it expresses a phenotype characterized by high innate anxiety levels, allowing to elucidate whether NP may exacerbate mood disorders at SCI chronic phase. After different photoinduction-times on exposed spinal cord, the mice developed a graded chronic hyperalgesia with minor to non-existent motor dysfunction. Behavioural data suggest that whilst hyperalgesia associated to SCI does not exacerbate BALB/c anxiety-like behaviours, it may result in depression-like behaviour at SCI chronic phase. Our study demonstrates that chronic central hyperalgesia may exacerbate despair-like behaviour at the SCI chronic phase in a mouse model of high anxiety-related behaviour. This implies that photochemical-SCI may be a suitable model to study the comorbidity between chronic NP and mood disorders. [ABSTRACT FROM AUTHOR]

• Only early, not late BCAS1+ cells increased in the peri -ischemic and remote areas. • Neither BCAS1+ cells nor Olig2 + cells were increased in SVD. • BCAS1 could be a specific marker for oligodendrogenesis in stroke and SVD. Ischemic cerebrovascular disease is an important cause of physical disability and dementia. Oligodendrocytes (OLGs), which differentiate from oligodendrocyte precursor cells (OPCs), are crucial for remyelination of the damaged brain and functional recovery. Breast carcinoma amplified sequence 1 (BCAS1) has recently been shown to be highly expressed in newly formed pre-myelinating oligodendrocytes (pre-mOLGs), while its expression level is reduced in mature OLGs. In this study, we analyzed BCAS1 expression by immunohistochemical analysis of human post-mortem brain tissue from six stroke patients (death within 2 months after stroke onset) and eight small vessel disease (SVD) patients. Control post-mortem brain tissue was from eight age-matched patients without any obvious central nervous system (CNS) pathology. The Olig2 expression in the area corresponding to the same section of the BCAS1-stained slice was analyzed to determine the total oligodendrocyte lineage. The percentage of differentiating OPCs in the oligodendrocyte lineage was calculated as the ratio of BCAS1+ to Olig2+ cells (BCAS1+/Olig2+). The stroke and SVD cases showed demyelination with decreased expression of myelin basic protein (MBP, a mature OLG marker). The stroke cases showed significantly increased numbers of early-stage BCAS1+ cells with an immature morphology and Olig2+ cells (pan-oligodendrocyte lineages) in the peri -infarct areas in both the cortex and white matter, but showed no increase in the number of late-stage BCAS1+ cells with a mature morphology. In contrast, the SVD cases showed no significant increase in Olig2+ and BCAS1+ cells. These results indicated that remyelination dysfunction could be attributed to insufficient maturation of OPCs in stroke and impaired recruitment of OPCs in SVD. [ABSTRACT FROM AUTHOR]

The sagittalis nucleus of the hypothalamus (SGN) is a small nucleus located in the interstitial area between the arcuate and ventromedial nuclei of the hypothalamus in rats. The SGN exhibits male-biased sexual dimorphism and expresses estrogen receptor α and calbindin-D28 K. This suggests a contribution of the SGN to sexually differentiated brain function, but its functional role is unknown. In this study, neuronal activation in the SGN during sexual behavior in male rats was examined by c-Fos immunohistochemistry. The number of c-Fos-immunoreactive (c-Fos-ir) cells was elevated with only exposure to chemosensory cues of estrous females and significantly increased after the first mount. The first intromission and ejaculation did not induce further increases in the number of c-Fos-ir cells in the SGN. These findings suggest that the SGN is involved in regulation of the early phase of male sexual behavior, including motivation. [ABSTRACT FROM AUTHOR]

Glioma, as the most common aggressive malignant tumor in the central nervous system, is still an insurmountable issue in neural diseases. The proliferation and survival mechanism of glioma cells need to be explored further for the development of glioma treatment. Hematopoietic cell-specific protein 1 associated protein X-1 (HAX-1) is well known for its anti-apoptotic effect. It was reported to play an important role in several malignant tumors. However, the effect of HAX-1 in glioma still remains unknown. This study aimed to investigate the expression of HAX-1 in glioma and the correlation between HAX-1 and the clinicopathological characteristics and prognosis of glioma. Quantitative reverse transcription polymerase chain reaction and Western blot analysis showed that HAX-1 was overexpressed in glioma cell lines compared with normal human astrocytes. This trend was confirmed by comparing the expression of HAX-1 in glioma tissues and nontumorous tissues. The study also analyzed the correlation between the expression of HAX-1 and clinicopathological characteristics of glioma and found the expression of HAX-1 to be highly related to the differentiation and World Health Organization stage of glioma tissues. The survival analysis revealed that HAX-1 was an independent prognostic factor. In conclusion, this novel study suggested that the overexpression of HAX-1 might contribute to the malignant progression of glioma. [ABSTRACT FROM AUTHOR]

Peripheral anorectic hormones, such as peptide YY (PYY) and oxytocin (OXT), suppress food intake. A newly identified anorectic neuropeptide, nesfatin-1, is synthesized in both peripheral tissue and the central nervous system, particularly by various nuclei in the hypothalamus and brainstem. Here, we examined the effects of intraperitoneal (ip) administration of PYY 3-36 , OXT, and OXT analog, on nesfatin-1-immunoreactive (ir) neurons in the rat hypothalamus and brainstem, using Fos double fluorescence-immunohistochemistry. The ip administration of OXT and OXT analog significantly increased the number of nesfatin-1-ir neurons expressing Fos-ir in the paraventricular nucleus, the arcuate nucleus, and the nucleus tractus solitarius, but not in the supraoptic nucleus, the lateral hypothalamic area, and the area postrema. No differences in the percentage of nesfatin-1-ir neurons expressing Fos in the nuclei of the hypothalamus and brainstem were observed, between rats treated with vehicle or those treated with PYY 3-36 . The decreased food intake, induced by OXT and OXT analog, was attenuated significantly by pretreatment with intracerebroventricular administration of antisense nesfatin-1. These results suggested that nesfatin-1-expressing neurons in the hypothalamus and brainstem may play a role in sensing the peripheral level of OXT and its suppression of feeding in rats. [ABSTRACT FROM AUTHOR]

Although rodent models of traumatic brain injury (TBI) reliably produce cognitive and motor disturbances, behavioral characterization resulting from left and right hemisphere injuries remains unexplored. Here we examined the functional consequences of targeting the left versus right parietal cortex in lateral fluid percussion injury, on Morris water maze (MWM) spatial memory tasks (fixed platform and reversal) and neurological motor deficits (neurological severity score and rotarod). In the MWM fixed platform task, right lateral injury produced a small delay in acquisition rate compared to left. However, injury to either hemisphere resulted in probe trial deficits. In the MWM reversal task, left-right performance deficits were not evident, though left lateral injury produced mild acquisition and probe trial deficits compared to sham controls. Additionally, left and right injury produced similar neurological motor task deficits, impaired righting times, and lesion volumes. Injury to either hemisphere also produced robust ipsilateral, and modest contralateral, morphological changes in reactive microglia and astrocytes. In conclusion, left and right lateral TBI impaired MWM performance, with mild fixed platform acquisition rate differences, despite similar motor deficits, histological damage, and glial cell reactivity. Thus, while both left and right lateral TBI produce cognitive deficits, laterality in mouse MWM learning and memory merits consideration in the investigation of TBI-induced cognitive consequences. [ABSTRACT FROM AUTHOR]

Feeding is a process controlled by a complex of associations between external and internal stimuli. The processes that involve learning and memory seem to exert a strong control over appetite and food intake, which is modulated by a gastrointestinal hormone, Ghrelin (Ghre). Recent studies claim that Ghre is involved in cognitive and neurobiological mechanisms that underlie the conditioning of eating behaviors. The expression of Ghre increases in anticipation of food intake based on learned behaviors. The hippocampal Ghre-containing neurons neurologically influence the orexigenic hypothalamus and consequently the learned feeding behavior. The CA1 field of Ammon's horn of the hippocampus (H-CA1) constitutes the most important neural substrate to control both appetitive and ingestive behavior. It also innervates amygdala regions that in turn innervate the hypothalamus. A recent study also implies that Ghre effects on cue-potentiated feeding behavior occur, at the least, via indirect action on the amygdala. In the present study, we investigate the neural substrates through which endogenous Ghre communicates conditioned appetite and feeding behavior within the CNS. We show the existence of a neural Ghre dependent pathway whereby peripherally-derived Ghre activates H-CA1 neurons, which in turn activate Ghre-expressing hypothalamic and amygdaloid neurons to stimulate appetite and feeding behavior. To highlight this pathway, we use two fluorescent retrograde tracers (Fluoro Gold and Dil) and immunohistochemical detection of Ghre expression in the hippocampus. Triple fluorescent-labeling has determined the presence of H-CA1 Ghre-containing collateralized neurons that project to the hypothalamus and amygdala monosynaptically. We hypothesize that H-Ghre-containing neurons in H-CA1 modulate food-intake behavior through direct pathways to the arcuate hypothalamic nucleus and medial amygdaloid nucleus. [ABSTRACT FROM AUTHOR]

The differential pharmacological responsiveness of cephalic and extra-cephalic neuropathic pain has been proposed to relate to distinct mechanisms that may involve neuroinflammatory reactions mediated by glial cells. Astrocytes are particularly important for neuronal sensitization in neuropathic pain, in part through modulation of glutamatergic transmission. Because the metabotropic glutamate receptor 5 (mGluR5) is involved in the astrocytic regulation of the glutamatergic system, we investigated modifications of its expression in models of cephalic versus extra-cephalic neuropathic pain. Adult male rats underwent unilateral chronic constriction injury (CCI) of either the infraorbital nerve (ION) or the sciatic nerve (SN). Seven days later, mGluR5 and the astrocyte marker GFAP (glial fibrillary acidic protein) were overexpressed and appeared localized mainly in the superficial lamina of the trigeminal nucleus in CCI-ION and the spinal cord dorsal horn in CCI-SN rats. In addition, colocalization of GFAP and mGluR5 strongly suggested an increase of astrocytic mGluR5 expression in nerve-injured rats compared to sham animals. The present data show an upregulation of astrocytic mGluR5 in central structures in both CCI-ION and CCI-SN. This suggests that the pharmacological modulation of mGluR5 could be a new approach to reduce both cephalic and extra-cephalic neuropathic pain. [ABSTRACT FROM AUTHOR]

It is well known that acetyl- l -carnitine (ALC) has various neuroprotective effects against neurodegenerative diseases. In addition, it has been reported that ALC facilitates myelination of regenerated axons after peripheral nerve injuries. We previously reported that spontaneous regeneration of the lateral olfactory tract (LOT), the main fiber tract of the central olfactory system, consistently occurred in newborn rats and a majority of these regenerated fibers were unmyelinated in neonatally LOT-transected young adult rats. To investigate the effects of ALC treatment on myelination in LOT, neonatal rats were treated with ALC after LOT transection. Immunohistochemistry for myelin basic protein showed more positive areas in ALC-treated rats than in control rats. Moreover, the number of myelinated axons of regenerated fibers was assessed using electron microscopy and was found to be statistically higher in ALC-treated rats compared to control rats. The study revealed that ALC accelerates myelination of regenerated fibers in neonatally LOT-injured young adult rats. [ABSTRACT FROM AUTHOR]

Acid-sensing ion channel 4 (ASIC4) belongs to the ASIC gene family of neuronal proton-gated cation channels, and is the least understood subtype among the members. Previous studies of ASIC4 expression in the mammalian central nervous system have shown that ASIC4 is abundantly expressed in the spinal cord and in various brain regions, such as the cerebral cortex, the hippocampus, and the cerebellum. However, the detailed distribution of ASIC4 transcripts in mammalian brains still remains to be elucidated. In the present study, radioactive in situ hybridization histochemistry with an ASIC4-specific cRNA probe was performed on wild-type mouse brains, followed by X-gal staining experiments with Asic4-lacZ reporter mice Asic4 tm1a(KOMP)Mbp . It was found that ASIC4 mRNAs were widely expressed throughout the wild-type brain, but preferentially concentrated in the olfactory bulb, the piriform cortex, the caudate putamen, the preoptic area, the paraventricular nucleus, the medial habenular nucleus, the pretectal area, the lateral geniculate nucleus, the amygdaloid complex, the superior colliculus, the interpeduncular nucleus, and the granule cell layer of the ventral hippocampus, and these results were in agreement with the X-gal-positive reactions observed in the mutant brain. In addition, X-gal staining combined with immunohistochemistry identified intense signals for ASIC4 transcriptional activity in most of the choline acetyltransferase (ChAT)-positive principal neurons located in the basal forebrain cholinergic nuclei. Our data provide useful information to speculate possible roles of ASIC4 in diverse brain functions. [ABSTRACT FROM AUTHOR]

Evidence suggests that diabetic ketoacidosis (DKA) may cause subtle cognitive alterations in children but the mechanisms are poorly understood. Acute DKA is associated with reactive astrogliosis and microglial activation in a rat model. Whether these inflammatory changes permanently alter brain histology is unknown. We aimed to determine whether DKA results in permanent alterations in brain histology and whether these changes are associated with cognitive deficits in a rat model. We induced diabetes in juvenile rats with streptozotocin at 4 weeks of age. We induced DKA in one group (n = 21) at 5 weeks of age and compared this group to rats with diabetes without DKA episodes (n = 13). Beginning at 7 weeks, rats underwent a series of cognitive tests to evaluate memory. At 15 weeks, rat brains were harvested and examined using immunohistochemistry (IHC). In tests of novel object recognition and social recognition, both groups performed similarly, however, the DKA group performed more poorly in object-place recognition tests, suggesting alterations in hippocampal function. IHC studies demonstrated increased glial fibrillary acidic protein staining intensity in the hippocampus of DKA rats suggesting astrogliosis, and decreased NeuN positive cell counts in the cortex suggesting neuron loss. These studies demonstrate that DKA results in permanent alterations in brain microstructure in a rat diabetes model. These structural changes are associated with deficits in hippocampal function. [ABSTRACT FROM AUTHOR]

The histopathological hallmark of Parkinson's disease (PD) and dementia with Lewy bodies (DLB) is the occurrence of insoluble fibrillary aggregates known as Lewy bodies, in which phosphorylated α-synuclein (α-syn) is a major component. To date, familial PD-linked gene products, including α-syn, parkin, PINK-1, DJ-1 and LRRK2, are known to be involved in Lewy body formation. Phospholipase A 2 , group VI ( PLA2G6 ) is the causative gene for PARK14 -linked parkinsonism (PARK14), a familial form of juvenile-onset dystonia parkinsonism. Several lines of evidence have suggested that PLA2G6 might play a role in the pathogenesis of not only PARK14, but also idiopathic PD. However, no published studies have investigated the association of PLA2G6 with the formation of Lewy bodies. In the present study, we used immunohistochemistry and Western blotting to investigate the involvement of PLA2G6 in Lewy body disease (PD and DLB), multiple system atrophy and Alzheimer's disease, in comparison with normal controls. Although cortical Lewy bodies, which lack a definable central core, were unstained with anti-PLA2G6 antibodies, the cores of brainstem-type Lewy bodies from PARK14 and idiopathic PD patients were moderately or intensely immunopositive for PLA2G6. Our results further reinforce the association of PLA2G6 with the pathogenesis of idiopathic PD, in addition to PARK14. [ABSTRACT FROM AUTHOR]

The dorsal raphe nucleus (DRN) is a major serotonin (5-hydroxytryptamine, 5-HT)-producing region in the central nervous system. It receives glutamatergic inputs from several brain regions, which are reciprocally modulated by serotonergic signals. We investigated whether serotonin 5-HT 4 receptors (5-HT 4 Rs) play a role in the development of glutamatergic control of the DRN, with an emphasis on cortical inputs. Double-label immunohistochemistry and confocal microscopy were used to quantify vesicular glutamate transporter 1 (vGluT1)-immunoreactive terminals in the DRN of mice with a null-mutation in the 5-HT 4 R gene. We found no significant change in the overall density of vGluT1-positive terminals in homozygous and heterozygous mice, but heterozygous mice had a significantly higher density of vGluT1-positive terminals contacting serotonergic neurons. These results suggest that altered 5-HT 4 R expression may affect the development of cortical glutamatergic control of the DRN. [ABSTRACT FROM AUTHOR]

In the present study, we describe the distribution of GABA C ρ3 receptor immunoreactivity in the cortex, striatum and hippocampus of wild type ( wt ) and 11 weeks old HD transgenic ( tg) R6/2 mouse brain. In the brain of wt mice, GABA C ρ3 immunoreactivity is well expressed in neuronal cells, nerve fibers and axonal processes. In comparison to wt, GABA C ρ3 receptor like immunoreactivity decreases significantly in all three brain regions of R6/2 mice. The altered distributional pattern and significant changes in GABA C ρ3 receptor immunoreactivity as seen in the R6/2 mouse brain might be a plausible molecular mechanism for excitotoxicity in HD pathogenesis due to the loss of inhibitory input. [ABSTRACT FROM AUTHOR]

The human craniofacial muscles innervated by the facial nerve typically lack muscle spindles. However these muscles have proprioception that participates in the coordination of facial movements. A functional substitution of facial proprioceptors by cutaneous mechanoreceptors has been proposed but at present this alternative has not been demonstrated. Here we have investigated whether other kinds of sensory structures are present in two human facial muscles (zygomatic major and buccal). Human checks were removed from Spanish cadavers, and processed for immunohistochemical detection of nerve fibers (neurofilament proteins and S100 protein) and two putative mechanoproteins (acid-sensing ion channel 2 and transient receptor potential vanilloid 4) associated with mechanosensing. Nerves of different calibers were found in the connective septa and within the muscle itself. In all the muscles analysed, capsular corpuscle-like structures resembling elongated or round Ruffini-like corpuscles were observed. Moreover the axon profiles within these structures displayed immunoreactivity for both putative mechanoproteins. The present results demonstrate the presence of sensory structures in facial muscles that can substitute for typical muscle spindles as the source of facial proprioception. [ABSTRACT FROM AUTHOR]

Galanin-like peptide (GALP) is a 60 amino acid neuropeptide originally discovered from porcine hypothalamus, and is involved in the regulation of food intake in mammals. Since its discovery, GALP and its receptors (GALR1 and GALR2) have been characterized in mammals, but no publications are available on GALP in fish and other non-mammals. The present study aimed to characterize brain and intestinal GALP and its receptors using immunohistochemistry in a teleost, the goldfish ( Carassius auratus ), and to study its effects on feeding behavior. Immunostaining of brain sections shows the presence of GALP- and GALR1- and GALR2-like immunoreactive cells in different encephalic areas, including the telencephalon, some hypothalamic nuclei, the optic tectum, the torus longitudinalis and the cerebellum. Signal for GALP was also observed in the fasciculus retroflexus . In the gut, GALP-and GALR1 and GALR2 immunoreactive cells were detected in the mucosa. Results from the feeding study demonstrate that intracerebroventricular administration of GALP (1 ng/g bodyweight) increases goldfish food intake at 1 h post-injection. These observations form the first report on the presence of GALP in the fish brain and gut, and also on its modulatory role on fish feeding behavior. GALP, as in mammals, appears to be a functional neuropeptide in goldfish. [ABSTRACT FROM AUTHOR]

• Sex differences in Iba1+ cells were assessed in the dentate gyrus (DG) of P10 mice. • Iba1+ cells were assessed in DG microglia-rich subregions: Hilus and Molecular Layer. • Both stereology and sampling approaches were used to quantify Iba1+ cells. • No sex difference found in Iba1+ cell number, density, or morphology in P10 mice DG. Microglia, the resident immune cells of the brain, support normal brain function and the brain's response to disease and injury. The hippocampal dentate gyrus (DG) is important for microglial study due to its central role in many behavioral and cognitive functions. Interestingly, microglia and related cells are distinct in female vs. male rodents, even in early life. Indeed, postnatal day (P)-dependent sex differences in number, density, and morphology of microglia have been reported in certain hippocampal subregions at specific ages. However, sex differences in the DG have not yet been assessed at P10, a translationally relevant time point as the rodent neuroanatomical eqivalent of human term gestation. To address this knowledge gap, Iba1+ cells in the DG (which are enriched in the Hilus and Molecular Layer) in female and male C57BL/6J mice were analyzed for their number (via stereology) and density (via stereology and via sampling). Next, Iba1+ cells were classified into morphology categories previously established in the literature. Finally, the percent of Iba1+ cells in each morphology category was multiplied by total cell number to generate a total number of Iba1+ cells in each category. Results show no sex difference in Iba1+ cell number, density, or morphology in the P10 Hilus or Molecular Layer. The lack of sex difference in Iba1+ cells in P10 DG using commonly-employed methodologies (sampling, stereology, morphology classification) provides a baseline from which to interpret microglia changes seen after injury. [ABSTRACT FROM AUTHOR]

• FoxP2 expression in the midbrain was examined in pre- and post-hatched chicks. • Foxp2 protein was decreased in the chick midbrain after hatching. • FoxP2-expressing cells were decreased in the SGFS of the midbrain after hatching. Forkhead-box subclass P member 2 (FOXP2/FoxP2) protein, a transcription factor, regulates the development of certain brain functions, including human speech and animal vocalization. Although rapid progress has been made in demonstrating a relationship between FoxP2 expression in the brain and vocalization of the zebra finch, a typical vocal learner, the relationship in avian vocal non-learners, including chickens remains elusive. Because the midbrain plays a key role in innate vocalization development, we analyzed the FoxP2 protein in the midbrain of chicks, which do not cheep before hatching but cheep and call after hatching. Western blot analyses showed a significant reduction in FoxP2 protein in the chick midbrain after hatching compared with the findings before hatching. Quantitative immunohistochemistry revealed that FoxP2-immunoreactive (ir) cells significantly decreased at the stratum gris fibrosum (SGFS) of the optic tectum in the chick midbrain after hatching compared with the findings before hatching. These findings support the notion that FoxP2-ir cell numbers decrease at a specific region in the midbrain after hatching may be involved in innate vocalization of avian vocal non-learners. [ABSTRACT FROM AUTHOR]

The forced swim test (FST) has been widely used for the preclinical evaluation of antidepressant drugs. Despite considerable differences in the protocol, equivalence of the FST for rats and mice has been rarely questioned. Previous research on the FST for rats revealed that repeated administration of antidepressant drugs attenuates the c-Fos response to swim stress in the hypothalamus and limbic regions. However, few studies have made similar investigations using the FST for mice. In the present study, we explored the mouse brain through immunohistochemistry staining for c-Fos after acute administration of imipramine or saline with or without a subsequent swim session. Imipramine enhanced the c-Fos density in regions of the central extended amygdala, while forced swim stress increased c-Fos expression in some hypothalamic (the ventrolateral preoptic nucleus and dorsomedial nucleus) and brain stem regions, which is consistent with previous reports. In contrast to previous literature with rats, swim stress brought a significant increase in c-Fos expression in the lateral septal nucleus and some other regions in the hypothalamus (the intermediate hypothalamic area, the paraventricular and arcuate nucleus) only in the imipramine-pretreated group, which has not been observed previously. In the arcuate nucleus, double immunostaining revealed that c-Fos was rarely co-expressed with proopiomelanocortin or tyrosine hydroxylase regardless of imipramine treatment. The present results suggest that the activation of several regions in the lateral septum and the hypothalamus underlies antidepressant-like effect in the mouse FST. [ABSTRACT FROM AUTHOR]

Several lines of evidence have demonstrated an inverse relationship between caffeine utilization and Parkinson's disease (PD) progression. Caffeine is a methylxanthine known as a non-specific inhibitor of adenosine (A 2A and A 1 ) receptors in the cerebrum and demonstrated to be a neuroprotective medication. In this study, the neuroprotective efficacy of two different doses of caffeine ranging above the usual consumption dose and below the toxic dose was investigated using histopathological and immunohistochemical methods. Thirty-two male rats were randomly divided into 4 groups, with 8 in each group: vehicle control (1 ml/kg/48 h for 12 days), rotenone (1.5 mg/kg/48 h, s.c. for 12 days), low-dose Caffeine-treated: (10 mg/kg IP. daily for 12 days), high-dose Caffeine-treated (20 mg IP daily for 12 days). Twenty-four hours after the last rotenone injection, animals were sacrificed and brains were sectioned and prepared for histopathological staining with hematoxylinand eosin, cresyl violet and Mallory’s phosphotungestic acid haematoxylinand for immunohistochemical staining of tyrosine hydroxylase. Our study showed that the treatment with caffeine improved histopathological degeneration in the substantia nigra parts compacta (SNpc) neurons and hindered the reduction in dopamine concentration caused by rotenone. We also found that a higher dose of caffeine was more effective against histopathological degeneration. These results suggest that caffeine has a dose-dependent neuroprotective effect. [ABSTRACT FROM AUTHOR]

Parkinson’s disease is a neurodegenerative disorder characterized by a loss of nigrostriata dopaminergic neurons, which has been thought, at least in part, to result from oxidative stress. The present study aims to investigate the neuroprotective effects of stemazole (ST) on the dopamine (DA) system and its possible mechanisms of action in a mouse model of PD. Mice were injected intraperitoneally with MPTP (20 mg/kg) four times at 2-h intervals for one day to induce Parkinsonism, and then treated with ST (10, 30 and 50 mg/kg) or Madopar (120 mg/kg) for 7 days. Behavioral analyses were performed with locomotor activity measures and rotarod test. Tyrosine hydroxylase (TH) and dopamine transporter (DAT) levels were detected by immunohistochemistry method. DA and its metabolites were determined by high-performance liquid chromatography with an electrochemical detector. Oxidative stress levels were assessed by measuring the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX). Our results demonstrated that ST treatment improved locomotor activity and motor coordination in MPTP mice. There was also a significant increase in TH-positive cells (∼24%, P < 0.01) and DAT levels (∼26%, P < 0.01) in MPTP mice treated with ST (50 mg/kg) compared with the vehicle group. Madopar treatment showed weaker effects on TH-positive cells (∼21%, P < 0.05) and DAT levels (∼21%, P < 0.05). DA and its metabolite levels were significantly increased with ST (50 mg/kg) treatment ( P < 0.01, compared with the vehicle group). In addition, SOD and GSH-PX activities were elevated notably in ST treatment groups compared with the vehicle group. In conclusion, these results suggest that ST has neuroprotective effect on the impaired DA system, potentially through enhancement of the cell’s anti-oxidative capacity. Hence it may be used as a potential therapeutic agent for Parkinson’s disease. [ABSTRACT FROM AUTHOR]

The objective of this study is to establish which subdivision of the dorsal raphe nucleus (DRN) supplies serotonergic projections to the subthalamic nucleus (STN) in the rat brain. Several studies in recent years have shown that serotonin (5-HT) might have a therapeutic role in the most prevalent basal ganglia (BG) movement disorder, Parkinson’s disease (PD), but, because of the depletion of dopaminergic input to the BG, l -DOPA has been the main treatment for PD patients. Autoradiography showed that serotonin receptors 5-HT 1B and 5-HT 2C and the serotonin transporter were present in STN, whereas the 5-HT 1A and 5-HT 2A not were present. Retrograde tracer FluoroGold or Choleratoxin subunit B were iontophoretically delivered in the STN and combined with immunohistochemistry for 5-HT in order to map the topographic organization in the dorsal raphe system. The study showed that approximately 320+/−137 neurons were retrogradely traced from each STN to the DRN, located mainly in the dorsal- and ventrolateral DRN, and of these 108+/−42 or 34% co-localized 5-HT. Additionally anterograde tracer PHA-L was injected in the DRN to confirm projections to STN and accordingly only a sparse number of axon terminals were observed in the STN. [ABSTRACT FROM AUTHOR]

Physical exercise has been identified as a preventive measure for Alzheimer’s disease (AD), one of the neuropathological hallmarks of which, neurofibrillary tangles, consist of hyperphosphorylated insoluble tau. Previous studies demonstrated that long-term treadmill exercise reduced tau hyperphosphorylation and insolubility; however, whether short-term treadmill exercise (STE) alters tau modifications currently remains unknown. In the present study, we attempted to characterize the effects of STE on tau solubility and determine its relationship with neuroinflammation using tauopathy model mice (Tg601), which express wild-type human tau. The results obtained showed that 3 weeks of non-shock treadmill exercise in Tg601 and non-transgenic female mice markedly increased insoluble tau. An analysis of phosphorylation patterns indicated that changes in tau solubility were related to an increase in phosphorylation at the tau C-terminal end. The results of immunohistochemical analyses revealed that STE increased the number of Iba-1-positive microglial cells in the hippocampus. Elevations in the levels of the lipid peroxidation markers, 4-hydroxy- trans -2-noneal and malondialdehyde, indicated the presence of oxidative stress. Moreover, higher levels of cytokines, IL-1β and IL-18, and chemokines, CXCL-1 and CXCL-12, supported neuroinflammation. [ABSTRACT FROM AUTHOR]

The aim of this study was to better understand the effect of amyloid-β plaques on magnetic resonance T2 relaxation time. We investigated these changes associated with age in an APP/PS1 mouse model of AD at 7 Tesla, combined with histology. Ten double-transgenic AD and ten wild type (WT) female mice (aged 12–20 months) were used in a cross-sectional study. Mean T2 values and standard deviations were calculated for each Regions of interest (ROIs) on T2 map. Immunohistochemistry for amyloid plaques and fluorescence staining with thioflavine S were performed of brain sections after imaging. The results showed that mean T2 values of the hippocampus, cortex, corpus callosum, and thalamus of older mice were significantly lower than of the younger. Compared to WT mice, the T2 values of the hippocampus, corpus callosum, and thalamus in younger AD mice were significantly greater, while the T2 values of the hippocampus and cortex in older AD mice were significantly less. Aβ-40 immunohistochemistry and thioflavine S stainging were positive in the matched region both for younger and older AD mice, while neither Aβ-40 nor thioflavine S were observed in WT mice. These findings suggest that regional T2 values of AD mice may decrease with age, and changes in T2 values in AD mice may be influenced by many factors besides amyloid-β plaque accumulation. Furthermore, they support that the standard deviation of the mean T2 value should be considered as well as the mean. [ABSTRACT FROM AUTHOR]

Cocaine-and amphetamine-regulated transcript peptides (CARTp) suppress gastric emptying and nutritional intake following 4th icv administration. Whereas, the CARTp inhibition of gastric emptying was blocked by pre-treatment with a non-selective corticotropin releasing factor (CRF) antagonist, sucrose drinking was not, suggesting that CARTp- and CRF controls for food intake and gastric emptying are operated through separable dorsal hindbrain mechanisms. The aim of the study was to explore CARTp–CRF brainstem interactions on patterns of neuronal activation in areas of the brainstem and midbrain relevant to gastrointestinal control and feeding regulation. Rats received 4th icv injections of combinations of vehicle, CARTp (1 μg), or the nonselective CRF antagonist, α-helical CRF9-41 (αCRF), in a randomized order. Brain sections were processed for c-fos by immunohistochemistry followed by image analysis at defined levels of the brain. CARTp (1 μg, 4th icv) induced a robust c-fos response in the nucleus of the solitary tract (NTS) and area postrema (AP), whereas, no c-fos could be detected in the parabrachial nucleus (PBN), the paraventricular nucleus of the hypothalamus (PVN) or the arcuate nucleus of the hypothalamus (ARC). The c-fos expression in the structures of the dorsal vagal complex (DVC) was completely blocked by pre-treatment with the CRF antagonist, which did not by itself induce c-fos at any examined level. After CARTp and αCRF in combination, there was a tendency towards an increased c-fos response in the ARC. We conclude that CARTp activates cells of the area postrema and NTS via a downstream, CRF-dependent mechanism. [ABSTRACT FROM AUTHOR]

Sortilin-related receptor CNS expressed 2 (SorCS2) is one of the vacuolar protein sorting 10 family proteins (VPS10Ps) that have pleiotropic roles in protein trafficking and intracellular and intercellular signaling. Bunina bodies (BBs) are specifically detected in the lower motor neurons in patients with amyotrophic lateral sclerosis (ALS). BBs are immunolabeled with antibodies against cystatin C, transferrin and peripherin and are considered to originate from the endoplasmic reticulum, which is part of the protein sorting pathway. The present study investigated whether VPS10Ps are involved in the formation of BBs in ALS. We immunohistochemically examined the spinal cord from patients with ALS and control subjects using antibodies against VPS10Ps (sortilin, SorLA, SorCS1, SorCS2 and SorCS3). In normal controls, antibodies against VPS10Ps immunolabeled the cytoplasm of anterior horn cells in a fine granular pattern. In ALS, almost all BBs (95.1%) were strongly immunopositive for SorCS2, and immunoreativity for sortilin and SorLA was decreased in anterior horn cells. These findings suggest that VPS10Ps may be involved in the disease process of ALS. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the antinociception of intrathecal amiloride and examine its effect on the neuropathic pain-induced activation of c-Fos and p-p38 MAPK in the rat spinal dorsal horn (SDH). Sprague-Dawley rats were chronically implanted with intrathecal catheters, and the ability of intrathecal amiloride to alleviate nociceptive behaviours in rats with neuropathic pain was tested. Immunohistochemical techniques were utilized to detect the expression of c-Fos and p-p38 in SDH in the control and amiloride (100 μg) groups. Intrathecal amiloride produced dose- and time-dependent antinociception in rats. Additionally, immunohistochemical experiments showed that the expression of c-Fos and p-p38 dramatically decreased in the superficial laminae of the ipsilateral SDH in the 100-μg amiloride group ( P < 0.01), whereas, there was no statistical significance on the contralateral side, compared with the control group. Intrathecally administered amiloride develops dose- and time-dependent antinociceptive action in rats with neuropathic pain. It most likely reduces spinal neurons and microglia activation via inhibiting c-Fos and p-p38 MAPK in the SDH of rats. [ABSTRACT FROM AUTHOR]

Transmission electron microscopy (TEM) is used for three-dimensional (3-D) analysis of synaptic connections in neuroscience research. However, 3-D reconstruction of the synapses using serial ultrathin sections is a powerful but tedious approach requiring advanced technical skills. High-voltage electron microscopy (HVEM) allows examination of thicker sections of biological specimens due to the increased penetration of the more accelerated electrons, which is useful to analyze the 3-D structure of biological specimens. However, it is still difficult to visualize the neural networks and synaptic connections in 3-D using HVEM because of insufficient and non uniform heavy metal staining in the membranous structures in semi-thin sections. Here, we present the successful chemical 3-D neuroanatomy of the rat spinal dorsal horn at the ultrastructural level as a first step for effective synaptome analysis by applying a high-contrast en bloc staining method to immune-HVEM tomography. Our new approach made it possible to examine many itch-mediating synaptic connections and neural networks in the spinal cord simultaneously using HVEM tomography. This novel 3-D electron microscopy is very useful for the analysis of synaptic structure and the chemical neuroanatomy at the 3-D ultrastructural level. [ABSTRACT FROM AUTHOR]

In the gastrointestinal (GI) tract of mammals, endings of spinal afferent neurons with cell bodies in dorsal root ganglia (DRG) detect many stimuli, including those that give rise to pain. Many of these sensory neurons express calcitonin gene-related peptide (CGRP) and TRPV1 in their cell bodies and axons. Indeed, CGRP and TRPV1 have been widely used as immunohistochemical markers of nociceptive spinal afferent axons. Although CGRP and TRPV1 often coexist in the same axons in the GI tract, their degree of coexistence along its length has yet to be quantified. In this study, we used double-labeling immunohistochemistry to quantify the coexistence of CGRP and TRPV1 in varicose axons of the murine oesophagus, stomach and colorectum. The great majority of CGRP-immunoreactive (IR) varicosities in myenteric ganglia of the lower esophagus (97 ± 1%) and stomach (95 ± 1%) were also TRPV1-immunoreactive. Similarly, the majority of TRPV1-IR varicosities in myenteric ganglia of the lower esophagus (95 ± 1%) and stomach (91 ± 1%) were also CGRP-IR. In the colorectum similar observations were made for an intensely immunoreactive population of CGRP-IR axons, of which most (91 ± 1%) were also TRPV1-IR. Of the TRPV1-IR axons in the colorectum, most (96 ± 1%) contained intense CGRP-IR. Another population of axons in myenteric ganglia of the colorectum had low intensity CGRP immunoreactivity; these showed negligible co-existence with TRPV1. Our observations reveal that in the myenteric plexus of murine oesophagus, stomach and colorectum, CGRP and TRPV1 are largely expressed together. [ABSTRACT FROM AUTHOR]

We investigated whether the loss of motor neuron-specific TDP-43 protein causes any change in the blood–spinal cord barrier (BSCB) in the spinal cord of TDP-43 conditional knockout (TDP CKO) mice. The TDP CKO mice were divided into four groups: early presymptomatic, late presymptomatic, early symptomatic, and late symptomatic stages. The spinal cords were pathologically examined. TDP CKO mice showed the activation of MAC-2 (macrophages/microglia) and fibrinogen exclusively in the anterior horn from the early symptomatic through the late symptomatic stages. Immunohistochemical and western blot analyses detected no reduction in tight junction proteins in TDP CKO mice as compared to age-matched wild-type mice at any stage. Electron-microscopically, TDP CKO mice showed vacuoles in the cytoplasm of most endothelial cells at the early symptomatic stage. The endothelium occasionally exhibited swollen cytoplasm by edematous fluid with the intact tight junction. The cytoplasm of the pericytes was relatively well preserved in contrast to the endothelial disruption. Extravascular or perivascular spaces were frequently edematous and vacuolated. At other stages, the BSCB was well preserved as in the controls. Thus, the temporary and reversible breakdown of the BSCB with leakage or increased permeability at the early symptomatic stage observed in this study could be a direct pathogenic consequence of the loss of TDP-43 protein, and the temporal impairment of BSCB, in turn, might contribute to the motor neuron degeneration in TDP CKO mice. [ABSTRACT FROM AUTHOR]

Serotonergic dysfunction is implicated in Alzheimer’s disease (AD). In addition, reductions in brain of both monoamine synthesis and release have been reported. Serotonin 1B receptors (5-HT1B), along with serotonin transporter (SERT) are among the regulators of extracellular 5-HT levels. We investigated the effect of the familial AD APP (Amyloid precursor protein) K670N/M671L double mutation, APP Swedish mutation (APPswe), on the expression of 5-HT1B, SERT, MAOA, p11 and 5-HT and its metabolite 5-HIAA in SH-SY5Y human neuroblastoma cell line stably transfected with APPswe mutation. In addition, hippocampal expressions of 5-HT1B and SERT were assessed in wild type and transgenic mice expressing APPswe mutation (Tg2576) at different age groups. We found a reduction of 5-HT1B as well as SERT in both APPswe in vitro and ex vivo . P11 and 5HT were also reduced, whereas 5HT turnover and MAOA were increased. Our results indicate that APPswe induced decreased 5-HT1B expression and 5-HT release, as well as increased MAOA activity and 5-HT breakdown. Further studies to explore the detailed mechanism behind reduced 5-HT1B and SERT in AD and their clinical implications are needed. [ABSTRACT FROM AUTHOR]

The prepositus hypoglossi nucleus (PHN) is a mossy fiber-generating precerebellar nucleus of the brainstem, regarded as one of the neural integrators of the vestibulo-ocular reflex. The aim of the present work is to reveal the distribution of various molecular components of the extracellular matrix (ECM) in the prepositus hypoglossi nucleus by using histochemical and immunohistochemical methods. Our most characteristic finding was the accumulation of the ECM as perineuronal net (PNN) and axonal coat and we detected conspicuous differences between the magnocellular (PHNm) and parvocellular (PHNp) divisions of the PHN. PNNs were well developed in the PHNm, whereas the pericellular positivity was almost absent in the PHNp, here a diffuse ECM was observed. In the PHNm the perineuronal net explored the most intense staining with the aggrecan, and tenascin-R antibodies followed by the hyaluronan, then least with reactions for chondroitin sulfate-based proteoglycan components and HAPLN1 link protein reactions, but PNNs were not observed with the versican, neurocan, and brevican staining. We hypothesized that the difference in the ECM organization of the two subnuclei is associated with their different connections, cytoarchitecture, physiological properties and with their different functions in the vestibular system. [ABSTRACT FROM AUTHOR]