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Metabolic disorders induce adverse effects on brain functions. The hippocampus is one of the most vulnerable regions to metabolic disorders. Disrupted neuroplasticity is a major cause of hippocampus-related behavioral impairments, including memory loss, anxiety, and depression. Astrocytes support processes of neuroplasticity. However, whether metabolic disorders induce changes in astrocytes and their roles in affective disorders is relatively unclear. To answer this question, we fed 8-week-old male C57BL/6 mice with a high-fat diet (HFD) for 12 weeks to induce metabolic disruption and then examined their performance of hippocampus-related memory, and anxiety- and depression-like behaviors. The morphology of astrocytes and the expression of astrocytic neuroplasticity-related proteins in the hippocampus were also assessed. The results showed that HFD led to obesity, systemic insulin resistance and dysregulated lipid metabolism in mice. HFD induced depression-like behaviors, but not anxiety or memory impairment. Furthermore, HFD increased the expression of GFAP, shortened the processes of GFAP + cells, and downregulated the expression of astrocytic neuroplasticity-related protein, GLAST, GLT-1, and connexin-43 in the hippocampi. In conclusion, HFD disturbs the function of hippocampal astrocytes and induces depression-like behaviors in mice. A decrease of hippocampal glutamate transporters may play a critical role in the pathogenesis of metabolic disorder-related depression., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Although it has been proved that remote limb preconditioning (RPC) can exert neurological protection effects after ischemic cerebral stroke (ICS), the underlying mechanisms of RPC still need to be elucidated for its better transformation to clinical application. Lipocalin-2 (LCN2) was upregulated after cerebral ischemia and mediated reperfusion injury in the models of ischemic stroke. So here, we investigated that whether RPC could downregulate the levels of LCN2 protein and its receptor resulting from cerebral ischemia reperfusion (I/R) injury. The results showed that RPC could decrease the expression of LCN2 protein, but having no obvious effects on its receptor except the time point of 72 h after cerebral ischemia. Furthermore, we observed the downregulation of Bim after RPC in the course of ICS., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Extensive changes occur at transcriptional level after traumatic spinal cord injury (SCI). In this study, we performed a large scale screening of expression changes of long (>200 nt) RNA transcripts including both coding and non-coding RNA species in a rat contusion SCI model. We validated significant down-regulation of one long non-coding RNA (lncSCIR1) at 1, 4, and 7 days postinjury. lncSCIR1 knockdown promoted astrocyte proliferation and migration in vitro. We further validated the strong association between lncSCIR1 knock down and the expression changes of four mRNAs after injury. Our data indicated that lncSCIR1 down-regulation might play a detrimental role in the pathophysiology of traumatic SCI and thereby provided new insights into the studies of potential therapeutic targets for traumatic central nervous system (CNS) injuries., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Abnormal oscillation in the cortical-basal ganglia loop is involved in the pathophysiology of parkinsonism. High-voltage spindles (HVSs), one of the main type abnormal oscillations in Parkinson's disease, are regulated by dopamine D2-like receptors but not D1-like receptors. However, little is known about how dopamine D2-like receptors regulate HVSs and the role of hyperpolarization-activated cyclic nucleotide-gated2 (HCN2) in HVSs regulation. We simultaneously recorded the local field potential (LFP) in globus pallidus (GP) and electrocorticogram (ECoG) in primary motor cortex (M1) in freely moving 6-hydroxydopamine (6-OHDA) lesioned or control rats. The expression of HCN2 and dopamine D2 receptor in the subthalamic nucleus (STN) was examined by immunochemical staining and Western blotting. We also tested the role of HCN2 in HVSs regulation by using pharmacological and shRNA methodology. We found that dopamine D2-like receptor agonists suppressed the increased HVSs in 6-OHDA lesioned rats. HCN2 was co-expressed with dopamine D2 receptor in the STN, and dopamine depletion decreased the expression of HCN2 as well as dopamine D2 receptor which contribute to the regulation of HVSs. HCN2 was down regulated by HCN2 shRNA, which thereby led to an increase in the HVSs in naïve rats while HCN2 agonist reduced the HVSs in 6-OHDA lesioned rats. These results suggest that HCN2 in the STN is involved in abnormal oscillation regulation between M1 cortex and GP., (Copyright © 2015 Elsevier B.V. All rights reserved.)

In adult rats, transection of the facial nerve causes a functional down-regulation of motoneurons and glial activation/proliferation. It has not been clear how energy-supplying systems are regulated in an axotomized facial nucleus. Here we investigated the regulation of molecules involved in glycogen degradation/synthesis in axotomized facial nuclei in rats. Immunoblotting revealed that the amounts of glycogen phosphorylase in the contralateral and ipsilateral nuclei were unchanged for the first 14 days, whereas the amount of glycogen synthase in the axotomized facial nuclei was significantly decreased from days 7-14 post-insult. A quantitative analysis estimated that the glycogen synthase levels in the transected nucleus were reduced to approx. 50% at 14 days post-injury. An immunohistochemical study showed that the injured motoneurons had decreased expressions of glycogen synthase proteins. The glycogen synthase levels in the axotomized facial nucleus had returned to control levels by 5 weeks post-insult, as had the cholinergic markers. The immunohistochemical study also revealed the recovery of glycogen synthase levels at the later stage. The glycogen phosphorylase levels in the injured nucleus were not significantly changed during weeks 3-5 post-insult. Taken together, these results demonstrated that the injured facial motoneurons transiently reduced glycogen synthase levels at around 1-2 weeks post-insult, but restored the levels at 4-5 weeks post-insult., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Nogo-A is a major form of growth inhibitory molecule (growth-IM) which inhibits axonal regeneration and neurite regrowth after neural injury. Bone marrow stromal cells (MSCs) have been shown to inhibit Nogo-A expression in vitro and in cerebral ischemic animal models. The present study was designed to investigate the effects of treatment with human MSCs (hMSCs) impregnated into collagen scaffolds on the expression of Nogo-A and axonal plasticity after traumatic brain injury (TBI). Adult male Wistar rats were injured with controlled cortical impact and treated either with saline, hMSCs-alone or hMSCs impregnated into collagen scaffolds (scaffold+hMSC) transplanted into the lesion cavity 7 days after TBI. Rats were sacrificed 14 days after TBI and brain tissues were harvested for immunohistochemical studies, Western blot analysis, laser capture microdissections and qRT-PCR to evaluate axonal density and Nogo-A protein and gene expressions. Our data showed that treatment of TBI with scaffold+hMSC significantly decreased TBI-induced Nogo-A protein expression and increased axonal density compared to saline and hMSC-alone treatments. In addition, scaffold+hMSC transplantation decreased Nogo-A transcription in oligodendrocytes after TBI. Scaffold+hMSC treatment was superior to hMSC-alone treatment in suppressing Nogo-A expression and enhancing axonal regeneration after TBI. Our data suggest that transplanting hMSCs with scaffolds down-regulates Nogo-A transcription and protein expression which may partially contribute to the enhanced axonal regeneration after TBI., (© 2013 Published by Elsevier B.V.)

Objective: To study the neural mechanism for the impact of negative emotional distraction on working memory in patients with posttraumatic stress disorder (PTSD) resulting from exposure to motor vehicle accidents., Methods: Twenty PTSD patients and 20 healthy subjects were recruited. Event-related functional magnetic resonance imaging (fMRI) was used to investigate the effects of negative and neutral distractors on a delayed-response working memory task. All experiments were performed on a 3.0T MRI scanner, and the functional imaging data were analyzed using SPM8 software., Results: The PTSD group showed poorer performance than the control group when the negative distractors were presented during the delay phase of working memory. The functional imaging indicated that, in the presence of negative relative to neutral distractors, the PTSD group showed higher activation in the emotion processing regions, including amygdala, precuneus and fusiform gyrus, but lower activation in the inferior frontal cortex, insula and left supramarginal gyrus than the control group., Conclusion: Based on the results that activation in the PTSD patients in the presence of negative distractors increased in the emotion-related brain regions but decreased in the working memory-related brain regions, we may conclude that the neural basis of working memory is impaired by negative emotion in PTSD patients., (© 2013 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Inflammatory and oxidative damage play a pivotal role in cerebral ischemic pathogenesis and may represent a therapeutic target. Octreotide (OCT) has been proved to elicit a variety of biological effects through its anti-inflammatory and anti-oxidant properties in the treatment of severe acute pancreatitis and ischemia-reperfusion injury in retina and intestine. However little is known regarding the effect of OCT in ischemic stroke. Here, we designed this study to investigate the protective effect of OCT in ischemic stroke and explore the potential underlying mechanisms., Methods: Male Sprague-Dawley rats were subjected to permanent middle cerebral artery occlusion (pMCAO) and randomly divided into four groups: Sham (sham-operated), MCAO (pMCAO+0.9% saline), OCT-L (pMCAO+OCT 50μg/kg) and OCT-H (pMCAO+OCT 100μg/kg) groups. OCT was administered intraperitoneally immediately after stroke. Neurological deficit scores, infarct volume and brain water content were measured at 24h after stroke. Immunohistochemical staining and western blot were used to analyze the expressions of Nrf2, HO-1 and NF-κB. SOD and MDA were measured by spectrophotometer., Results: Compared with MCAO group, OCT significantly alleviated neurological deficit, lessened infarct volume and brain edema (P<0.05), upregulated the expression of Nrf2, HO-1 and SOD (P<0.05), and decreased the expression of NF-κB and MDA (P<0.05)., Conclusions: OCT protected the brain against cerebral ischemic damage; this effect may be through upregulation of transcription factor Nrf2, HO-1 and downregulation of NF-κB expression., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Motor cortex stimulation (MCS) is a promising clinical procedure to help alleviate chronic pain. Animal models demonstrated that MCS is effective in lessening nocifensive behaviors. The present study explored the effects of MCS on cortical somatosensory evoked potentials (SEPs) recorded at the primary somatosensory cortex (SI) of the rat. SEPs were evoked by electrical stimulation applied to the contralateral forepaws. Effects of different intensities, frequencies, and durations of MCS were tested. MCS at ≥2V suppressed SEPs of the ipsilateral SI. Suppression lasted 120 min at an intensity of 5 V. The optimal frequency was 50 Hz, and the duration was 30s. In contrast, MCS did not affect SEPs recorded on the contralateral SI. Cortical stimulation out of the motor cortex did not induce a decrease in the ipsilateral SEPs. We also investigated involvement of the endogenous opioid system in this inhibition of SEPs induced by MCS. The opioid antagonist, naloxone (0.5 mg/kg), was administered 30 min before MCS. Application of naloxone completely prevented the inhibitory effect of MCS on ipsilateral SEPs. These results demonstrate that MCS blocked the transmission of somatosensory information to the primary somatosensory cortex, and this interference was mediated by the endogenous opioid system. This inhibitory effect on sensory transmission induced by MCS may reflect its antinociceptive effect., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Presbycusis is the impairment of auditory function associated with aging, which stems from peripheral cochlear lesions and degeneration of the central auditory process. The effect of age-induced peripheral hearing loss on the central auditory process is not fully understood. C57Bl/6 (C57) mice present accelerated peripheral hearing loss, which is well developed by middle-age and mimics the human presbycusis pattern. The aim of this study was to elucidate the molecular effects of peripheral hearing loss in the inferior colliculus (IC) with age between young and middle-aged C57 mice using cDNA microarray. Glutamate receptor ionotropic NMDA ζ1 (GluN1) exhibited the greatest decrease in the middle-aged group as determined using cDNA microarray and by further assessment using real-time PCR (qPCR). Histological assessment with in situ hybridization of GluN1 showed significantly decreased expression in all IC subdivisions of the middle-aged group. GluN1 is a receptor for excitatory neurotransmission, and significant downregulation of this gene may be subsequent to the decline of afferent input from the cochlea in aging C57 mice. Consequently, using the combination of microarray, qPCR, and in situ hybridization, we showed that the decline of GluN1 in the IC of aging animals might have a key role in the pathogenesis of presbycusis., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Exendin-4 is a GLP-1 agonist that is clinically used for the treatment of diabetes mellitus and may also have neuroprotective effect. We explored the effect of repeated administration of exendin-4 (0.5 μg/kg, intraperitoneal twice a day for 7 days) on infarct volume, neurological deficit (neurological score, grip test, foot fault and rota rod tests), oxidative stress parameters (malondialdehyde, reduced glutathione, and superoxide dismutase) and expression of endothelin (ET) ET(A) and ET(B) receptors following cerebral ischemia produced in rats by permanent middle cerebral artery occlusion (MCAO). Since ET(A) receptors in the central nervous system (CNS) are involved in cerebral ischemia, we determined the effect of a specific ET(A) receptor antagonist, BQ123 (1mg/kg, intravenously administered thrice: 30 min, 2h and 4h after MCAO for a total dose of 3 mg/kg) on cerebral ischemia in control and exendin-4 treated rats. Results indicate that exendin-4 treated rats had significant protection following MCAO induced cerebral ischemia. The infarct volume was 27% less compared to vehicle treated rats. The neurological deficit following MCAO was lower and oxidative stress parameters were improved in exendin-4 treated rats compared to control. BQ123 significantly improved infarct volume, oxidative stress parameters and neurological deficit in ischemic rats treated with vehicle or exendin-4. BQ123 induced protection from cerebral ischemia was similar in vehicle or exendin-4 treated rats. Expression of ET(A) receptors was significantly increased following cerebral ischemia which was not affected by exendin-4 treatment or by BQ123 administration. No change in expression of ET(B) receptors was observed following cerebral ischemia or any treatment. It is concluded that exendin-4 protects the CNS from damage due to cerebral ischemia by reducing oxidative stress and is independent of ET receptor involvement., (Copyright © 2011 Elsevier B.V. All rights reserved.)

We investigated the mechanism underlying inhibition of spinal dorsal horn GABAergic neurotransmission to elucidate the role of protease-activated receptor-2 (PAR2). Initially, we confirmed that PAR2 agonist SL-NH(2) applied intrathecally produced mechanical hyperalgesia. Then we performed patch-clamp experiments in substantia gelatinosa neurons of spinal cord slice, and found that spontaneous inhibitory post-synaptic currents (sIPSCs) were significantly decreased in both frequency and amplitude when neurons were incubated with PAR2 agonist SL-NH(2) for a brief time period (2 min). The GABA-mediated currents were significantly reduced, and there was no impact on glycine-mediated currents during this SL-NH(2) treatment. These results suggest that PAR2 activation enhanced the pain response, potentially via inhibition of dorsal horn GABAergic neurotransmission., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Hypothyroidism can lead to depressed breathing. We determined if propylthiouracil (PTU)-induced hypothyroidismin hamsters (HH) altered dopamine D1 receptor expression, D1 receptor-modulated ventilation, and ventilatory chemoreflex activation by hypoxia or hypercapnia. Hypothyroidism was induced by administering 0.04% PTU in drinking water for 3 months. Ventilation was evaluated following saline or 0.25mg/kg SCH 23390,a D1 receptor antagonist, while awake hamsters breathed normoxic (21% O(2) in N(2)), hypoxic (10% O(2)in N(2)) and hypercapnic (5% CO(2) in O(2))air. Relative to euthyroid hamsters (EH), HH exhibited decreased D1 receptor protein levels in carotid bodies, striatum, and hypothalamic paraventricular nucleus, but not in the nucleus tractus solitarius. Relative to EH, HH exhibited lower ventilation during exposure to normoxia, hypoxia, or hypercapnia, but comparable ventilatory responsiveness to chemoreflex activation. SCH23390 decreased ventilation of EH hamsters exposed to normoxia, hypoxia, and hypercapnia. In HH SCH23390 increased ventilation during baseline normoxia and did not affect ventilation during exposure to hypoxia and hypercapnia, resulting in reduced ventilatory responsivess to chemoreflex activation by hypoxia and hypercapnia. Furthermore, in HH D1 receptor protein levels are decreased in several brain regions and within the carotid bodies. Moreover, D1 receptor-modulation of breathing at rest and during gas exposures were depressed in EH but not HH., (Copyright © 2011 Elsevier B.V. All rights reserved.)

A prolonged exposure to vibration stimuli triggers pathological changes with many later manifested symptoms. Early vibration-induced changes are still not very well explored. Therefore, short 30 min vibration period per day with frequency 60 Hz repeated for 10 days was used, and the retrograde axonal transport from the sciatic nerve, the expression of calcitonin gene-related peptide (CGRP) and parvalbumin (PV) were studied in the dorsal root ganglia (DRGs) corresponding to lower lumbar spinal levels. Repeated vibration markedly decreased (25 and 34%) the accumulation of retrogradely transported Fluorogold to spinal motor neurons, whereas a significant increase (35 and 25%) was seen in the DRG primary sensory neurons corresponding to the L4 and L5 spinal level. Immunohistochemical studies showed a significant reduction of CGRP-positive small-sized neuronal cells in both DRGs. Fluoro-Jade labeling revealed that marked loss of CGRP-imunoreactive DRG sensory neurons is not due to neuronal degeneration. CGRP protein expression determined by Western blot analysis and optical density measurement, and NGF level measured by ELISA have been decreased, markedly only at the L4 DRG. PV protein expression was not affected by short repeated vibrations. Our results indicate that (a) short-lasting repeated vibrations affect the retrograde axonal transport in the DRG sensory neurons differently than in spinal motor neurons; (b) a decreased NGF-dependent CGRP production in the DRG primary sensory neurons plays an important role in early vibration-induced pathological mechanisms., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Collapsin response mediator protein2 (CRMP2) is a brain-specific protein involved in neuronal polarity and axonal guidance, and phosphorylation of CRMP2 regulates the function and the activity. CRMP2 has shown to be implicated in several neurodegenerative diseases (Alzheimer's disease, epilepsy and ischemia) and this study was designed to assess the role of CRMP2 in periventricular leukomalacia (PVL). We developed a PVL model using 3-day-old rats to investigate the expression and phosphorylation of CRMP2 in the newborn brain. Hypoxia-ischemia was applied by unilateral carotid ligation followed by exposure to 5% oxygen for 30min. Pathological changes were evaluated from 0h to 21d post-HI, and white matter damage including severe necrosis, white matter rarefaction and lateral ventricle dilatation were found. In the PVL model astrogliosis and axonal damage were detected in the injured white matter by immunohistochemistry at 48-168h post-HI, and delayed myelination was verified by Western blotting after 21-day post-HI. We confirmed that this model showed neuropathological features of PVL. Next, significant changes of CRMP2 were observed in the brain of the PVL model. Western blotting and immunohistochemistry showed that cleavage and hypo-phosphorylation of CRMP2 occurred after 48h post-HI in the PVL brain. Our results suggest that cleaved CRMP2 could represent hypo-phosphorylated-CRMP2 and HI could induce activation of CRMP2 in the PVL brain. The activated CRMP2 may play an important role in neuronal plasticity in PVL. Our findings suggest that future treatment strategies of PVL should target the phosphorylation mechanism of CRMP2., (Copyright © 2010 Elsevier B.V. All rights reserved.)

Wnt signaling is important in various neuropsychiatric diseases. However, its actions on modulating schizophrenia are largely unknown. Our previous study found that three SNPs in adenomatous polyposis coli (APC), a negative regulator of the Wnt signaling, were associated with schizophrenia, and the mRNA levels of APC in blood leucocytes of patients with schizophrenia were significantly increased. This prompted us to further investigate the effects of Wnt signaling components on the pathogenesis of schizophrenia. In our current study, mouse schizophrenia was induced by i.p. injection of MK-801 for 7days and the brain prefrontal cortex (PFC) and ventral tegmental area (VTA) were isolated to investigate the Wnt signaling pathway. Compared with control, schizophrenic mice had increased inhibitory phosphorylation of glycogen synthase kinase 3beta (GSK-3beta) in PFC and VTA, which is disassociated with augmented beta-catenin phosphorylation. However, APC mRNA and protein in the PFC and VTA isolated from the schizophrenic group were increased and matched with increased beta-catenin phosphorylation. The total dendritic length was significantly increased in both PFC and VTA from MK-801-treated mice compared to control. By using cultured SK-N-SH and PC12 cells with and without transfection of APC siRNA, we found that the APC protein facilitates neurite growth in vitro. Our data suggested that MK-801-induced schizophrenia is associated with attenuated Wnt signaling pathway in the brain, which may be due to augmented APC protein during schizophrenia. APC facilitates neurite growth, potentially contributing to the pathology of schizophrenia., (Crown Copyright © 2011. Published by Elsevier B.V. All rights reserved.)

Sensory experience influences brain organization and function. A particularly striking example is in the olfactory bulb where reduction of odorant sensory signals profoundly down-regulates dopamine in glomerular neurons. There are two large populations of glomerular inhibitory interneurons: (1) GABAergic periglomerular (PG) cells, whose processes are limited to a single glomerulus, regulate intraglomerular processing and (2) DAergic-GABAergic short axon (SA) cells, whose processes contact multiple glomeruli, regulate interglomerular processing. The inhibitory neurotransmitter GABA is synthesized from L-glutamic acid by the enzyme glutamic acid decarboxylase (GAD) of which there are two major isoforms: GAD65 and GAD67. GAD65 is expressed in uniglomerular PG cells. GAD67 is expressed by SA cells, which also co-express the rate-limiting enzyme for dopamine synthesis, tyrosine hydroxylase (TH). Deafferentation or sensory deprivation decreases TH expression but it is not known if sensory input alters GAD isoforms. Here we report that either deafferentation or reduction of sensory input by nares occlusion significantly reduced GAD67 protein and the number of SA cells expressing GAD67. However, neither manipulation altered GAD65 protein or the number of GAD65 PG cells. These findings show that sensory experience strongly impacts transmitter regulation in the circuit that controls neural processing across glomeruli but not in the circuit that regulates intraglomerular processing., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Unlabelled: Excessive exposure to Mn induces neurotoxicity, referred to as manganism. Exposure assessment relies on Mn blood and urine analyses, both of which show poor correlation to exposure. Accordingly, there is a critical need for better surrogate biomarkers of Mn exposure. The aim of this study was to examine the relationship between Mn exposure and early indicators of neurotoxicity, with particular emphasis on peripheral biomarkers. Male Wistar rats (180-200g) were injected intraperitoneally with 4 or 8 doses of Mn (10mg/kg). Mn exposure was evaluated by analysis of Mn levels in brain and blood along with biochemical end-points (see below)., Results: Brain Mn levels were significantly increased both after 4 and 8 doses of Mn compared with controls (p<0.001). Blood levels failed to reflect a dose-dependent increase in brain Mn, with only the 8-dose-treated group showing significant differences (p<0.001). Brain glutathione (GSH) levels were significantly decreased in the 8-dose-treated animals (p<0.001). A significant and dose-dependent increase in prolactin levels was found for both treated groups (p<0.001) compared to controls. In addition, a decrease in motor activity was observed in the 8-dose-treated group compared to controls., Conclusions: (1) The present study demonstrates that peripheral blood level is a poor indicator of Mn brain accumulation and exposure; (2) Mn reduces GSH brain levels, likely reflecting oxidative stress; (3) Mn increases blood prolactin levels, indicating changes in the integrity of the dopaminergic system. Taken together these results suggest that peripheral prolactin levels may serve as reliable predictive biomarkers of Mn neurotoxicity., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Sophocarpine, one of the major alkaloid compounds isolated from Sophora pachycarpa, is highly valued and important in traditional Chinese medicine. In the present study, we aimed to explore the possible mechanisms underlying sophocarpine-mediated neuroprotection against transient focal cerebral ischemia. Sophocarpine (5, 10, or 20mg/kg) was given 30min before focal ischemia was induced in rats by occlusion of the middle cerebral artery. After sophocarpine treatment, the total infarct volume was significantly decreased in comparison to the ischemia-reperfusion values. The results of a neurological evaluation were significantly improved in the sophocarpine treated group when compared to controls. The number of TUNEL-positive cells was significantly reduced compared to the untreated ischemic group. Results of Western blotting and immunohistochemical staining indicated that pretreatment with sophocarpine down-regulated the expression of acid-sensing ion channel 1 (ASIC1) in the ischemic cortex. These results suggest that sophocarpine ameliorated the ischemic injury induced by transient focal cerebral ischemia in rats and that this neuroprotective effect might be related to the anti-ASIC1 channel and anti-apoptotic action of sophocarpine., (Copyright © 2011 Elsevier B.V. All rights reserved.)

We examined the histologic findings of optic nerve axons and changes in kinesin-1, which is involved in axonal flow, in N-methyl-d-aspartate (NMDA)-induced neurotoxicity in rats. Substantial degenerative changes visualized as black profiles and pale large axons were observed 72h after NMDA injection, but those degenerative changes were not apparent in axons 12 and 24h after injection. Morphometric analysis showed a significant, approximately 40% reduction in the number of axons 72h after NMDA injection. Immunohistochemical study showed that there was a recognizable loss of neurofilament-immunopositive dots, but myelin basic protein immunostaining was unchanged 72h after NMDA injection. Western blot analysis showed early elevation of kinesin-1 (KIF5B) protein levels in the retina 24 and 72h after NMDA injection. Conversely, significant decreases in KIF5B protein levels in the optic nerve were seen during the same time course. Immunohistochemical study also showed that there was a reduction in KIF5B immunoreactivity in axons, but neurofilament immunostaining was unchanged 24h after NMDA injection. These findings suggest that the intravitreal injection of NMDA causes neurofilament loss without myelin alteration in the early stage. The depletion of kinesin-1 precedes axonal degeneration of the optic nerve in NMDA-induced neurotoxicity., (Copyright © 2010 Elsevier B.V. All rights reserved.)

The inability of axons in central nervous system (CNS) to regenerate after injury is related partly to multiple endogenous axon growth inhibitors including Nogo receptor (NgR). This study tested the hypothesis that silencing NgR expression by adenovirus-mediated RNA interference (RNAi) (AD-NgR) may permit axonal connectivity after focal cerebral ischemia in rats. Male Sprague-Dawley rats (250-280g, n=97) were assigned into seven groups: sham, MCAO (24h and 2 weeks), MCAO plus AD-NgR (24h and 2 weeks), and MCAO plus AD-HK (control oligonucleotides) (24h and 2 weeks). After cerebral ischemia, NgR mRNA and protein in the cortex and hippocampus were significantly increased at 24h and 2 weeks. However, in AD-NgR treated rats, NgR mRNA and protein were reduced by 40-60% in the cortex and hippocampus at both time points as compared to controls. Although there was no significant difference in the infarct volume between the two groups, the number of midline-crossing fibers projecting to the contralateral red nucleus and corticostriatal fibers in the dorsolateral striatum were increased in AD-NgR injected rats, accompanied by improved behavioral outcomes. Taken together, these results suggest that NgR knockdown may promote CNS axonal regeneration and functional recovery after ischemic cerebral injury., (Copyright © 2010 Elsevier B.V. All rights reserved.)

Malignant gliomas have a high proliferation ability and high tendency to invade diffusely into surrounding healthy brain tissues, thereby precluding their successful surgical removal. Intersectin1 (also called ITSN1) as a molecular linker in the central nervous system is well known as an important regulator of endocytosis and exocytosis. ITSN1 has two isoforms: ITSN1-l and ITSN1-s. In this study, we show that siRNA-mediated down regulation of ITSN1-s induced glioma cells apoptosis. In addition, we demonstrate the possible mechanisms by which ITSN1-s functions in glioma cells apoptosis. Our data demonstrate that several key proteins, including FAK, Akt, Bcl-2, BAD which are critical for cells apoptosis were probably involved in ITSN1-s signaling pathways. Our results indicate that ITSN1-s is an effecter in regulation of gliomas cells apoptosis, and identify that ITSN1-s may be a new potentially anti-apoptosis target for therapeutic of gliomas., (2010 Elsevier B.V. All rights reserved.)

Bcl-2 interacting cell death suppressor (Bis), also known as Bag3, has been implicated in anti-stress and anti-apoptotic pathways. In a previous study, we observed a significant induction of Bis in reactive astrocytes of the rat hippocampus after transient forebrain ischemia. To investigate the significance of this induction in ischemic injury, the expression of Bis was reduced with siRNA in C6 glioma cells and exposed to oxygen-glucose deprivation (OGD) conditions. Bis knock-down resulted in an increase in the cell death rate of the C6 cells after OGD, accompanied by accumulation of reactive oxygen species. Among the cellular antioxidants, the induction of superoxide dismutase (SOD) activity was significantly interfered within the cells treated with bis siRNA treated cells (bis-kd C6). A Western blot assay revealed that SOD1 expression gradually increased in control cells, which was not observed in bis-kd cells upon OGD treatment. A quantitative analysis of Sod1 and Sod2 transcripts indicated that the induction of Sod1 was more evidently suppressed by the reduction of Bis. As a transcription factor candidate for the Sod1 gene, the activity of NF-kappaB was determined the nuclear translocation of p65, showing that the activation of NF-kappaB was attenuated in bis-kd C6. Supporting this, an overexpression of Bis augments the activation of NF-kappaB and Sod1 mRNA with an increased cell survival under OGD conditions. These results suggest that one of physiological significances of Bis induction in reactive astrocytes after ischemia in vivo is to protect glial cells from oxidative stress, probably via the induction of SOD1, which is related to the activation of NF-kappaB., (Copyright 2010 Elsevier B.V. All rights reserved.)

Oxidative stress and high levels of reactive oxygen species (ROS) are risk factors of auditory cell injury and hearing impairment. MicroRNAs (miRNAs) are critical for the post-transcriptional regulation of gene expression and cell proliferation and survival. However, little is known about the impact of oxidative stress on the expression of miRNAs and their targeted mRNAs in auditory cells. We employed a cell model of oxidative stress by treatment of House Ear Institute-Organ of Corti 1 (HEI-OC1) cells with different concentrations of tert-butyl hydroperoxide (t-BHP) to examine the t-BHP-induced production of ROS and to determine the impact of t-BHP treatment on the relative levels of miRNA and mRNA transcripts in HEI-OC1 cells. We found that treatment with different concentrations of t-BHP promoted the production of ROS, but inhibited the proliferation of HEI-OC1 cells in a dose- and time-dependent manner. Furthermore, treatment with t-BHP induced HEI-OC1 cell apoptosis. Further microarray analyses revealed that treatment with t-BHP increased the transcription of 35 miRNAs, but decreased the expression of 40 miRNAs. In addition, treatment with t-BHP up-regulated the transcription of 2076 mRNAs, but down-regulated the levels of 580 mRNA transcripts. Notably, the up-regulated (or down-regulated) miRNAs were associated with the decreased (or increased) expression of predicted targeted mRNAs. Importantly, these differentially expressed mRNAs belonged to different functional categories, forming a network participating in the oxidative stress-related process in HEI-OC1 cells. Therefore, our findings may provide new insights into understanding the regulation of miRNAs on the oxidative stress-related gene expression and function in auditory cells., (Copyright 2010 Elsevier B.V. All rights reserved.)

PK11195 was previously reported to attenuate the quinolinic acid (QUIN)-induced enhancement of glucose metabolism in rat brain. In the present study, the effect of PK11195 or anesthesia on [(14)C]2-deoxyglucose ([(14)C]DG) uptake was investigated in order to determine whether the QUIN-induced enhancement of glucose metabolism occurred in glial cells or neurons. We confirmed that the microinjection of QUIN caused a significant enhancement of [(14)C]DG uptake at 2h after the infusion, while the co-injection of PK11195 and QUIN almost completely suppressed this enhancement of [(14)C]DG uptake. No effect of chloral hydrate anesthesia on the QUIN-induced enhancement of [(14)C]DG uptake was observed. In contrast to rats treated with QUIN, PK11195 did not affect the enhancement of [(14)C]DG uptake induced by fluorocitrate (FC); however, chloral hydrate anesthesia completely suppressed the FC-induced increase in [(14)C]DG uptake. These results indicated that the enhancement of glucose metabolism induced by QUIN mainly occurred in glial cells, and the neuroprotective effect of PK11195 in rats injected with QUIN might be related to the suppression of anaerobic glycolysis in glial cells., ((c) 2010 Elsevier B.V. All rights reserved.)

Hyperalgesia is one of the debilitating complications of diabetes. This condition might be caused by defects in central or peripheral processing of pain signals. In the present study we aim to see if diabetic hyperalgesia is related to changes in Transient Receptor Potential Vanilloid 1 (TRPV1) or Cannabinoid CB1 receptors of periaqueductal gray (PAG). Activation of glutamatergic projecting neurons in midbrain ventrolateral periaqueductal gray (VL-PAG) induces antinociception. Agonists of TRPV1 in VL-PAG increase firing of these glutamatergic neurons. CB1 receptor agonists also cause antinociception by decreasing Gamma Aminobutyric Acid (GABA) release in PAG and disinhibiting these glutamatergic neurons. In the present study antinociceptive effect of intra VL-PAG microinjections of CB1 and TRPV1 agonists [WIN55,212-2 (WIN) and capsaicin respectively] were compared in diabetic vs. non-diabetic rats, meanwhile mRNA expression of these receptors in PAG of diabetic and non-diabetic rats were evaluated by real time polymerase chain reaction (real time PCR) assay. Our results showed an attenuation of capsaicin antinociceptive effect (P<0.05) and TRPV1 receptor expression (P=0.023) but an increase in WIN antinociceptive effect (P<0.05) and CB1 receptor expression (P<0.001) in PAG of diabetic vs. non-diabetic rats. It is concluded that down-regulation of TRPV1 receptors in PAG is responsible for reduced antinociceptive effect of TRPV1 agonist. This finding may be an underlying cause of diabetic hyperalgesia. Up-regulation of CB1 receptors might be a compensatory mechanism but the precise elucidation of the effects of CB1 changes on disinhibition needs further studies., (Copyright 2010 Elsevier B.V. All rights reserved.)

Over-activation of NMDA receptor has been widely believed to be the main signal resulting in ischemic cell injury. We recently reported that the triplicate complex NR2A-PSD-95-Src is a signaling module to facilitate NMDA receptor over-activation. In addition, over-activation of NMDA receptor can activate another signaling molecule nNOS, which is also mediated by PSD-95 after cerebral ischemia. Here, we examined whether overexpression of the PDZ1 domain of PSD-95 could disrupt the functional interaction between NMDA receptor and PSD-95 in rat hippocampal CA1 region, and whether or not it could exert a neuroprotective effect against cerebral ischemia. Our results showed that overexpression of PDZ1 domain not only decreased the assembly of NR2A-PSD-95-Src signaling module and the auto-phosphorylation of Src, which mediates NMDA receptor phosphorylation, but also enhanced nNOS (Ser847) phosphorylation. Most importantly, overexpression of PDZ1 domain protected rat hippocampal CA1 neurons against cerebral ischemia injury. These results suggest that overexpression of the PDZ1 domain can perturb the binding of PSD-95 to NMDA receptor, suppress the activity of both NMDA receptor and nNOS, and thus have a neuroprotective effect., (Copyright 2010 Elsevier B.V. All rights reserved.)

Inflammation and immune response have been implicated in the pathogenesis of cerebral vasospasm after subarachnoid hemorrhage (SAH). Recently, increased TLR4 expression has been associated with the development of cerebral vasospasm in a rabbit model of SAH. Peroxisome proliferator-activated receptor gamma (PPARgamma) agonists, effective inhibitors of TLR4 activation, may modulate the vasospasm progression via their anti-inflammation effects. We investigate whether the blood component oxyhemoglobin (OxyHb) can induce the expression of Toll-like receptor (TLR) 4 in vascular smooth muscle cells (VSMCs), and evaluate the modulatory effects of PPARgamma agonist rosiglitazone on OxyHb-induced inflammation in VSMCs. Cultured VSMCs incubated with or without rosiglitazone were exposed to OxyHb at 10muM for up to 48h. Expression of TLR4 was assessed by immunocytochemistry and Western blot analysis. Production of tumor necrosis factor alpha (TNF-alpha) in conditioned medium were quantified by ELISA. A marked increase of TLR4 production and TNF-alpha release was observed at 48h after cells were treated with OxyHb. Rosiglitazone reduced TLR4 immunocytochemistry staining and protein production significantly in VSMCs. A specific antagonist for PPARgamma, GW9662, could reverse the anti-inflammatory effects of rosiglitazone. The results demonstrated that OxyHb exposure could induce TLR4 activation in cultured VSMCs. Rosiglitazone suppressed TLR4 expression and cytokine release via the activation of PPARgamma and may have a therapeutic potential for the treatment of vasospasm following SAH., (Copyright 2010 Elsevier B.V. All rights reserved.)

In males, long-term alcohol consumption provokes neurochemical changes in the medial parvocellular division of the PVN (PVNmp) that are partially reversed by withdrawal. Because gonadal steroids modulate the activity of the hypothalamo-pituitary-adrenal axis, we analyzed the possibility that the repercussions of chronic alcohol consumption and withdrawal on the anatomy and neurochemistry of the PVNmp might differ between the sexes. Male and female Wistar rats were examined after ingesting a 20% alcohol solution for 6 months or after 2 months of withdrawal from 6 months of alcohol consumption. The levels of gonadal steroids and the basal concentrations of corticosterone were also evaluated. Chronic alcohol consumption and withdrawal did not alter the global cytoarchitectonic features of the PVNmp in rats of both sexes. However, alcohol consumption was associated with a decrease in the number of vasopressin (VP) neurons only in females and of corticotropin releasing hormone (CRH) neurons in males and females. Further, the response to withdrawal was sexually dimorphic because in males there was a partial recovery of the number of CRH neurons whereas in females there was a further loss of VP and CRH neurons. Corticosterone levels were unchanged by alcohol consumption, but they were decreased by withdrawal in females. Alcohol consumption and withdrawal did not alter estrogen and progesterone concentrations in females, but decreased testosterone levels in males. These findings show that the response of CRH and VP neurons to excess alcohol is gender-specific, with females being more vulnerable during alcohol consumption and, most notably, after withdrawal.

Valproate (VPA) is a commonly prescribed mood stabilizer. However, emerging evidence indicates that VPA administration may cause reversible symptoms of Parkinsonism and cognitive decline (P/CD) in some manic patients. The mechanism of this phenomenon is unknown. In this study, we used human SY5Y neuroblastoma cells as a neuronal model to investigate the effects of VPA on neurite outgrowth and neurofilament expression. Data showed that the treatment with VPA at therapeutic plasma levels (0.5 mM) significantly reduced cell proliferation from day 4 through day 6, and neurite outgrowth length from day 1 through day 6. Conversely, VPA had no effect on cell proliferation of human CCF astrocytoma cells but stimulated nerve growth factor (NGF)-induced neurite outgrowth from rat PC12 pheochromocytoma cells. In parallel to these alterations in human SY5Y cells, both mRNA and protein levels of neurofilament 160 (NF160) were significantly reduced, starting at day 2 and day 3, respectively, by the treatment. The inhibition of neurite outgrowth by VPA was completely reversed 2 days after cessation of VPA exposure. Furthermore, NF160 protein levels also rebounded to control levels after VPA removal. NGF application significantly alleviated the inhibition of neurite outgrowth by VPA. These data suggest that VPA-modulated NF160 expression was involved in the inhibition and the reversal of neurite outgrowth in human neuronal cells.

Hormone deficiency following ovariectomy causes activation of Na(+),K(+)-ATPase and acetylcholinesterase (AChE) that has been related to cognitive deficits in experimental animals. Considering that physical exercise presents neuroprotector effects, we decide to investigate whether exercise training would affect enzyme activation in hippocampus and cerebral cortex, as well as adenosine nucleotide hydrolysis in synaptosomes from cerebral cortex of ovariectomized rats. Female adult Wistar rats were assigned to one of the following groups: sham (submitted to surgery without removal of the ovaries), exercise, ovariectomized (Ovx) and Ovx plus exercise. Thirty days after surgery, animals were submitted to one month of exercise training, three times per week. After, rats were euthanized, blood serum was collected and hippocampus and cerebral cortex were dissected. Data demonstrated that exercise reversed the activation of Na(+),K(+)-ATPase and AChE activities both in hippocampus and cerebral cortex of ovariectomized rats. Ovariectomy decreased AMP hydrolysis in cerebral cortex and did not alter adenine nucleotides hydrolysis in blood serum. Exercise per se decreased ADP and AMP hydrolysis in cerebral cortex. On the other hand, AMP hydrolysis in blood serum was increased by exercise in ovariectomized adult rats. Present data support that physical exercise might have beneficial effects and constitute a therapeutic alternative to hormone replacement therapy for estrogen deprivation.

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.

Astroglial cells clear extracellular glutamate through the glutamate transporters, GLT-1 and GLAST, and subsequently convert the incorporated glutamate into glutamine by the enzyme, glutamine synthetase (GS). Several forms of acute brain injury are associated with the increased expression of GS and the decreased expression of GLT-1 and/or GLAST, eventually leading to the accumulation of excitotoxic extracellular glutamate concentrations. Although of clinical interest, the actual trigger of these injury-related changes of glial glutamate turnover remains unknown. Our present studies provide evidence that increases in extracellular glutamate, as present in many brain injuries, are sufficient to modulate the expression of glutamate transporters and GS. Subjecting cultured cortical astrocytes to glutamate concentrations of 0.5-20 mM resulted in a 25% loss of GLT-1 and GLAST protein levels after 24 h; GLT-1 and GLAST levels maximally decreased by 40% and 75%, respectively, after 72 h. This decline was not due to astroglial cell death, since glutamate up to 50 mM did not affect the survival of cultured astrocytes within 72 h. Major astrocytic cell death, however, occurred in cultures maintained under severe (4% O(2)), but not mild (9% O(2)), hypoxia, as well as in the presence of aspartate (>or=20 mM). Glutamate at >or=1 mM induced a prolonged increase of GS expression in contrast to glutamate transporters. Neither the decline of glutamate transporter expression nor the increase in GS expression induced by high extracellular glutamate was further modulated by mild hypoxia. Whereas the stimulatory influences of glutamate on GS expression were prevented by the non-competitive NMDA receptor antagonist, MK801, the inhibitory influences on glutamate transporter expression were neither sensitive to MK801, the non-competitive mGluR5 antagonist, MTEP, nor the non-competitive AMPA receptor antagonist, GYKI52466, implying that glutamate controls glial glutamate transport by a glutamate receptor-independent mechanism.

The lack of productive infection of neurons by HIV-1 suggests that the neuronal damage seen in AIDS patients with cognitive disorders is caused indirectly via viral and cellular proteins with neurotoxic activity. Among HIV-1 proteins, Vpr has been shown to deregulate expression of various important cytokines and inflammatory proteins in infected and uninfected cells. However, the mechanisms underlying these changes remain unclear. Here, we demonstrate that neurons can take up Vpr that is released into the supernatant of HIV-infected microglia. We also found that administration of recombinant Vpr (rVpr) to human neurons resulted in a slow but sustained elevation of intracellular calcium [Ca(2+)]i. Interestingly, our data also show that [Ca(2+)]i elevation by Vpr leads to ROS production and impairs glutamate signaling in neuronal cells. Vpr disturbs calcium homeostasis through downregulation of endogenous PMCA. Finally, we found that the permeability of the plasma membrane increases in neurons treated with Vpr. Therefore, we conclude that soluble Vpr is a major viral factor that causes a disturbance in neuronal communication leading to neuronal dysfunction. The outcome of these studies will advance the understanding of HIV-1 pathogenesis and will help in the development of new therapeutic approaches.

Several recent studies suggest that sumo-2/3 modification of proteins occurs following harmful ischemia, however, sumo-2/3-ylation may also be associated with hibernation-mediated neuroprotection. Here we investigate the sumoylation of proteins following ischemia and ischemic tolerance using our established in vitro model of ischemia (oxygen and glucose deprivation; OGD). Following harmful ischemia (120 min OGD), we observed a significant increase in the sumo-2/3-ylation of high molecular weight proteins (>85 kDa), but not sumo-1-ylation of proteins. Sumo-2/3-ylation following 120 min OGD was reduced when cultures were preconditioned with non-harmful 30 min OGD 24 h earlier (delayed ischemic tolerance). However, we observed no change in sumo-2/3-ylation in a model of rapid ischemic tolerance. The effects of preconditioning on sumo-2/3-ylation following harmful ischemia were blocked by the protein synthesis inhibitor cycloheximide (1.0 muM), a known inhibitor of delayed ischemic tolerance. In addition, we observed a reduction in sumo-2/3-ylation using hypothermia (4 degrees C 30 min) as the preconditioning stimuli to induce delayed ischemic tolerance. Further studies show that sumo-2/3-ylation occurs during the ischemic insult and that preconditioning does not change expression of the sumo E1- and E2-ligases (UBA2 and Ubc9) or the sumo specific isopeptidases (SenP1-3). While sumo-2/3-ylation is enhanced under conditions of cell stress, it is not yet clear whether this is a cause or consequence of harmful ischemia-induced cell damage.

Brain injury represents a major health problem and may result in chronic inflammation and neurodegeneration. Due to antiinflammatory effects of gold, we have investigated the cerebral effects of metallic gold particles following a focal brain injury (freeze-lesion) in mice. Gold particles 20-45 microm in size or the vehicle (placebo) were implanted in the cortical tissue followed by a cortical freeze-lesioning. At 1-2 weeks post-injury, brains were analyzed by using immunohistochemistry and markers of inflammation, oxidative stress and apoptosis. This study shows that gold treatment significantly reduces the cerebral levels of tumor necrosis factor alpha (TNFalpha), oxidative DNA damage (as judged by 8-oxoguanine levels), and pro-apoptotic markers (cleaved caspase-3, cytochrome c leakage), when compared to those of controls. The data presented here points toward gold particles as a tool to modulate the cerebral response to injury.

Recently, we could demonstrate in rats that a short transient oligemic period of only 20-minute duration, induced by systemic hypotension, resulted in a transient decline of spatial memory capacities without any histological damage over a subsequent period of 6 months. In our present study, we checked for more subtle alterations within the highly vulnerable hippocampal CA1 subfield using quantification of neuronal cell density and semi-quantitative analysis of the ischemia-sensitive protein MAP2. Since hippocampal excitatory and inhibitory neurotransmitter receptors are crucially involved in spatial memory processes, quantitative in vitro receptor autoradiography was performed using [(3)H]MK-801, [(3)H]AMPA, and [(3)H]muscimol for labeling of NMDA, AMPA, and GABA(A) receptors, respectively. Ligand binding values were analyzed in the ischemia-sensitive hippocampal formation and in the parietal cortex. Transient oligemia did not cause any reduction of the neuronal cell density in the vulnerable CA1 subfield nor did it cause any significant changes of MAP2 protein expression in the dendritic layers of CA1. After oligemia, hippocampal binding densities of NMDA, AMPA, and GABA(A) receptors remained unchanged in all subfields investigated. Similarly, there was no difference in cortical ligand binding values of the excitatory NMDA and AMPA receptors comparing oligemic to sham-operated control rats. In the parietal cortex, however, transient oligemia caused a significant reduction of [(3)H]muscimol binding values compared to controls. These findings demonstrate long-term changes in receptor binding densities even after short oligemic periods possibly reflecting part of the molecular basis leading to impaired cognitive abilities.

The genetically epilepsy-prone rat (GEPR) exhibits inherited predisposition to sound stimuli-induced generalized tonic-clonic seizures (audiogenic reflex seizures) and is a valid model to study the physiopathology of epilepsy. In this model, the inferior colliculus (IC) exhibits enhanced neuronal firing that is critical in the initiation of reflex audiogenic seizures. The mechanisms underlying IC neuronal hyperexcitability that leads to seizure susceptibility are not as yet fully understood. The present report shows that the levels of protein expression of SK1 and SK3 subtypes of the small conductance Ca2+-activated K+ channels were significantly decreased, while SK2 channel proteins were increased in IC neurons of seizure-naive GEPR-3s (SN-GEPR-3), as compared to control Sprague-Dawley rats. No significant change was found in the expression of BK channel proteins in IC neurons of SN-GEPR-3s. Single episode of reflex audiogenic seizures in the GEPR-3s did not significantly alter the protein expression of SK1-3 and BK channels in IC neurons compared to SN-GEPR-3s. Thus, downregulation of SK1 and SK3 channels and upregulation of SK2 channels provide direct evidence that these Ca2+-activated K+ channels play important roles in IC neuronal hyperexcitability that leads to inherited seizure susceptibility in the GEPR.

Neurodegeneration is a characteristic feature of AIDS dementia complex and is commonly associated with neuronal death in the brains of both pediatric and adult patients. Neuronal death associated with AIDS dementia complex can be induced by the HIV-1 protein gp120, but the underlying signal transduction mechanism remains unclear, especially for HIV-1 subtypes commonly seen in China. We have now demonstrated that the human CC ligand 3-like protein 1 (CCL3L1), a member of the CC chemokine family, appears to protect neuronal cultures through its ability to attenuate gp120-induced neuronal death. We found that (i) both pCREB levels and Bcl-2 expression are up-regulated in neuronal culture following treatment with CCL3L1 plus gp120; (ii) CCL3L1 induces cell survival via phosphorylation of CREB by way of the PKA and CaMKI/CaMKIV cell signaling pathways; (iii) transcription of the cell survival gene bcl-2 is induced by pCREB; and (iv) CCL3L1 protects cultured neurons against CCR5-mediated excitotoxicity induced by gp120. Thus, the CCL3L1/bcl-2-regulated anti-apoptotic pathway significantly contributes to reduction of HIV-1/gp120-induced neuronal apoptosis, and therefore, CCL3L1 should be further investigated as a potential chemokine to protect against neuronal injury in gp120-related neuronal toxicity.

Pregnancy is characterized by elevated heart rate and decreased total peripheral resistance and arterial blood pressure. Plasma volume is expanded and plasma osmolality is decreased, yet vasopressin secretion in pregnant animals, including humans, is no different than levels in the nonpregnant state. Although reflex compensatory sympathoexcitation is suppressed, baseline sympathetic nerve activity to the heart and vasculature is well maintained or slightly elevated in pregnancy. Clearly there are central nervous system (CNS) adaptations in systems for regulation of cardiovascular and body fluid homeostasis in pregnant animals. The paraventricular nucleus (PVN) and supraoptic nucleus (SON) of the hypothalamus are important CNS sites for control of sympathetic nerve activity and vasopressin secretion. Nitric oxide (NO), an important neuromodulator in these hypothalamic nuclei, contributes to tonic inhibition of neurosecretory and pre-autonomic neurons. Alterations in NO within the PVN and SON could contribute to changes in regulation of vasopressin and sympathetic nerve activity in pregnancy. In the present study, nitric oxide synthase (NOS) activity (NADPH-diaphorase staining), neuronal NOS (nNOS) protein, and nNOS mRNA were assessed in nonpregnant estrus stage and near-term pregnant rats. nNOS mRNA, protein, and activity were greater in the PVN than in the SON. In the PVN only, pregnancy was associated with significant decreases in all three measurements for assessment of nNOS. Thus decreased NO production and relative disinhibition of the PVN may contribute to maintenance of baseline vasopressin secretion and baseline sympathetic nerve activity in the pregnant state.

The present study determined the effect of maternal nicotine exposure during the early developmental period on AT(1)R and AT(2)R mRNA and protein abundance in the rat brain. Pregnant rats of day-4 gestation were implanted with osmotic minipumps that delivered nicotine at a dose rate of 6 mg/kg/day for 28 days. Neither fetal nor offspring brain weight was significantly altered by the nicotine treatment. Nicotine significantly increased brain AT(1)R in fetuses at gestation 15 and 21 days and decreased central AT(2)R at gestation day 21. In the offspring, perinatal nicotine significantly increased brain AT(1)R protein in males but not females at 30 days, and increased it in both males and females at 5-month-old. AT(2)R protein levels were significantly decreased by nicotine in both male and female offspring regardless of ages. Whereas brain AT(1)R mRNA abundance did not change during postnatal development, AT(2)R mRNA levels in both sexes significantly decreased in 5-month-old, as compared with 30-day-old offspring. Nicotine significantly increased brain AT(1)R mRNA in the female offspring. In contrast, it decreased AT(2)R mRNA in the brain to the same extent in males and females. In control offspring, there was a developmental increase in the AT(1)R/AT(2)R mRNA ratio in the brain of adult animals, which was significantly up-regulated in nicotine-treated animals with females being more prominent than males. The results demonstrate that perinatal nicotine exposure alters AT(1)R and AT(2)R gene expression pattern in the developing brain and suggest maternal smoking-mediated pathophysiological consequences related to brain RAS development in postnatal life.

In this study event related coherence of patients with Alzheimer type of dementia (AD) was analyzed by using a visual oddball paradigm as stimuli. A total of 21 mild probable AD subjects (10 untreated, 11 treated) were compared with a group of 19 healthy controls. The members of the groups had their EEG recorded from 12 electrodes by means of a visual oddball paradigm. The evoked coherence was analyzed for delta (1-3.5 Hz), theta (4-7 Hz) and alpha (8-13 Hz) frequency ranges for inter-hemispheric (F3-F4, C3-C4, T3-T4, T5-T6, P3-P4, O1-O2) and long range intra-hemispheric (F3-P3, F4-P4, F3-T5, F4-T6, F3-O1, F4-O2) electrode pairs. The control group showed higher values of evoked coherence in "delta", "theta" and "alpha" bands in the left fronto-parietal electrode pairs in comparison with the untreated AD group (p<0.01 for all frequency bands). Furthermore, the control group showed higher values of evoked coherence in the left fronto-parietal electrode pair in theta frequency band (p<0.01) and higher values of evoked coherence in the right fronto-parietal electrode pair in delta band (p<0.01) when compared to treated AD group. The only significant difference between the treated and untreated AD groups was in the alpha band. The treated AD group showed higher values of evoked coherence at the left fronto-parietal pair in alpha band in comparison to the untreated AD group (p<0.01). During a working memory process the coherence in the left fronto-parietal electrode pair (F3-P3) of AD patients is significantly decreased, thus indicating reduced connectivity between frontal and parietal sites.

Neuritic dystrophy with amyloid burden and neurofibrillary tangles are pathological hallmarks of Alzheimer's disease. Genetic disruption of CD40 or CD40L alleviates amyloid burden, astrocytosis, and microgliosis in transgenic animal models of Alzheimer's disease. It has been reported that phosphorylated tau-positive dystrophic neurites are observed in transgenic mice over-expressing human mutant beta-amyloid precursor protein (Tg2576). Here, we studied the pattern of phosphorylated tau (labeled with AT8, CP13, PG5, and PHF1 antibodies) and plaques using immunohistochemical techniques. Phosphorylated tau-positive dystrophic neurites were exclusively associated with Congo red-positive plaques as previously reported. Further, we show that CD40L or CD40 deficiency reduces the mean ratio of dystrophic neurite area to congophilic plaque area and the level of expression of cdk5 and p35/p25 in mice. In addition, we show that in a human neuroblastoma cell line treated with CD40L, cdk5 and p35/p25 are increased. Together, our data suggest that CD40-CD40L interaction has an effect on tau phosphorylation independent of beta-amyloid pathology, and that this effect may occur through a decrease of cdk5 and p35/p25.

NT69L, is a novel neurotensin (8-13) analog that participates in the modulation of the dopaminergic pathways implicated in addiction to psychostimulants. NT69L blocks nicotine-induced hyperactivity as well as the initiation and expression of sensitization in rats. Recent evidence suggests that stimulation of mesocorticolimbic dopamine system, with influences from the other monoamine systems, e.g. norepinephrine and serotonin, is involved in nicotine's reinforcing properties. The aim of the present study was to investigate the effect of pretreatment with NT69L on nicotine-induced changes in monoamine levels in the rat brain using in vivo microdialysis. Acute or chronic (0.4 mg/kg, sc, once daily for 2 weeks) administration of nicotine elicited increases in extracellular levels of dopamine, dopamine metabolites, norepinephrine, or serotonin in medial prefrontal cortex, nucleus accumbens shell, and core of rats. Pretreatment with NT69L (1 mg/kg, intraperitoneally, ip) administered 40 min before nicotine injection significantly attenuated the acute nicotine-evoked increases in norepinephrine levels in medial prefrontal cortex, dopamine and serotonin in nucleus accumbens shell. After chronic nicotine administration, pretreatment of NT69L markedly reversed the increase in dopamine levels in the nucleus accumbens core. NT69L's attenuation of some of the biochemical effects of acute and chronic nicotine is consistent with this peptide's attenuation of nicotine-induced behavioral effects. These data further support a role for NT69L or other neurotensin receptor agonists to treat nicotine addiction.

Individuals with homozygous deficiency in cystathionine-beta-synthase (CBS) develop high levels of homocysteine in plasma, a condition known as homocysteinuria. Mental retardation ensues with death in teens; the heterozygous live normally but develop vascular dementia and Alzheimer's disease (AD) in later part of life. The treatment with muscimol, a gamma amino butyric acid receptor-A (GABA(A)) agonist, mitigates the AD syndrome and vascular dementia. We tested the hypothesis that homocysteine (Hcy) antagonizes the GABA(A) receptor and behaves as an excitotoxic neurotransmitter that causes blood brain barrier (BBB) permeability and vascular dementia. The BBB permeability was measured by infusing Evan's blue dye (2% in saline 5 ml/kg concentration) in CBS-/+, GABA(A)-/-, CBS-/+/GABA(A)-/- double knockout, CBS-/+ mice treated with muscimol and wild type (WT) mice. Matrix Metalloproteinase (MMP-2, MMP-9), Tissue Inhibitor of Matrix Metalloproteinase (TIMP-3, TIMP-4), collagen-III and elastin levels were measured in whole brain by Western blot. These results suggested an increase in Evan's blue permeability: CBS-/+

Curcumin is a major active component isolated from Curcuma longa. Previously, we have reported its significant antidepressant effect. However, the mechanisms underlying the antidepressant effects are still obscure. In the present study, we explored the effect of curcumin against glutamate excitotoxicity, mainly focusing on the neuroprotective effects of curcumin on the expression of Brain-Derived Neurotrophic Factor (BDNF), which is deeply involved in the etiology and treatment of depression. Exposure of rat cortical neurons to 10 microM glutamate for 24 h caused a significant decrease in BDNF level, accompanied with reduced cell viability and enhanced cell apoptosis. Pretreatment of neurons with curcumin reversed the BDNF expression and cell viability in a dose- and time-dependent manner. However, K252a, a Trk receptor inhibitor which is known to inhibit the activity of BDNF, could block the survival-promoting effect of curcumin. In addition, the up-regulation of BDNF levels by curcumin was also suppressed by K252a. Taken together, these results suggest that the neuroprotective effect of curcumin might be mediated via BDNF/TrkB signaling pathway.

The relationship between tyrosine availability and high potassium (K+) induced dopamine (DA) and norepinephrine (NE) efflux was examined in striatum using in vivo microdialysis. High K+ (80 mM) was included in perfusate for two 30 min periods, 2.5 h apart. After the first high-K+ perfusion, a tyrosine- and phenylalanine-free mixture of large neutral amino acids (LNAA(-)) was administered (IP) to lower brain tyrosine. Tyrosine (0, 25, 50 or 100 mg/kg IP) was administered 30 min prior to the second high-K+ perfusion. The ratio of catecholamine efflux during the two perfusions (P2/P1) was compared between groups. LNAA(-) significantly lowered P2/P1 for both DA and NE. Tyrosine 25-50 mg/kg blocked the LNAA(-) effect. We conclude that catecholamine efflux during prolonged depolarization is tyrosine dependent. Analyses of LNAA levels suggest that availability of tyrosine for tyrosine hydroxylation may be modulated by competition between LNAAs within brain extracellular fluid.

In the hippocampus, BK channels are preferentially localized in presynaptic glutamatergic terminals including mossy fibers where they are thought to play an important role regulating excessive glutamate release during hyperactive states. Large conductance calcium-activated potassium channels (BK, MaxiK, Slo) have recently been implicated in the pathogenesis of genetic epilepsy. However, the role of BK channels in acquired mesial temporal lobe epilepsy (MTLE) remains unknown. Here we used immunohistochemistry, laser scanning confocal microscopy (LSCM), Western immunoblotting and RT-PCR to investigate the expression pattern of the alpha-pore-forming subunit of BK channels in the hippocampus and cortex of chronically epileptic rats obtained by the pilocarpine model of MTLE. All epileptic rats experiencing recurrent spontaneous seizures exhibited a significant down-regulation of BK channel immunostaining in the mossy fibers at the hilus and stratum lucidum of the CA3 area. Quantitative analysis of immunofluorescence signals by LSCM revealed a significant 47% reduction in BK channel immunofluorescent signals in epileptic rats when compared to age-matched non-epileptic control rats. These data correlate with a similar reduction in BK channel protein levels and transcripts in the cortex and hippocampus. Our data indicate a seizure-related down-regulation of BK channels in chronically epileptic rats. Further functional assays are necessary to determine whether altered BK channel expression is an acquired channelopathy or a compensatory mechanism affecting the network excitability in MTLE. Moreover, seizure-mediated BK down-regulation may disturb neuronal excitability and presynaptic control at glutamatergic terminals triggering exaggerated glutamate release and seizures.

Neonatal quinpirole (dopamine D(2)/D(3) agonist) treatment to rats has been shown to increase dopamine D(2) receptor sensitivity throughout the animal's lifetime. Male and female Sprague-Dawley rats were neonatalally treated with quinpirole (1 mg/kg) from postnatal days (P) 1-21 and raised to adulthood. Beginning on P62, rats were administered the atypical antipsychotic olanzapine (2.5 mg/kg) twice daily for 28 days. Starting 1 day after the end of olanzapine treatment, animals were behaviorally tested on the place and match-to-place version of the Morris water maze (MWM) over seven consecutive days, and a yawning behavioral test was also performed to test for sensitivity of the D(2) receptor 1 day following MWM testing. Similar to results from a past study, olanzapine alleviated cognitive impairment on the MWM place version and increases in yawning produced by neonatal quinpirole treatment. Brain tissue analyses showed that neonatal quinpirole treatment resulted in a significant decrease of hipppocampal ChAT and BDNF RNA expression that were unaffected by adulthood olanzapine treatment, although adulthood olanzapine treatment produced a significant increase in cerebellar ChAT RNA expression. There were no significant effects of drug treatment on NGF RNA expression in any brain area. These results show that neonatal quinpirole treatment produced significant decreases of protein RNA expression that is specific to the hippocampus. Although olanzapine alleviated cognitive deficits produced by neonatal quinpirole treatment, it did not affect expression of proteins known to be important in cognitive performance.

In a search for novel genes involved in the hypothalamic control of body energy homeostasis bioinformatic tools were applied. Analysis of the presence of structural features characteristic for secretory peptides was used as a first step in the identification of novel neuropeptides, and was followed by analysis of expression patterns. The gene product previously named TAFA5 was identified during this process. The overall mRNA expression pattern of TAFA5 was assessed using quantitative PCR on rat cDNA libraries. Furthermore, the brain mRNA and polypeptide expression patterns were examined in rats using in situ hybridization and immunohistochemistry. Our results substantiate previous findings that TAFA5 is mainly expressed in the central nervous system. Furthermore, we found TAFA5 mRNA to be highly expressed in the hypothalamic paraventricular nucleus (PVN) where it co-localized with vasopressin and oxytocin in magno- and parvocellular neurons. Immunohistochemical analysis revealed TAFA5 immunoreactivity in the PVN in accordance with the in situ hybridization data. Given the high levels of expression in the PVN, it was investigated whether TAFA5 mRNA levels were affected by fasting or dehydration. Interestingly, it was observed that TAFA5 mRNA was specifically down-regulated in the PVN following water deprivation. Based on our findings we suggest that TAFA5 may be involved in the regulation of fluid homeostasis.