Neuroscience letters
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Neuroscience letters · Mar 2015
Activation of cannabinoid receptor 1 inhibits increased bladder activity induced by nerve growth factor.
Nerve growth factor (NGF) is an important mediator of inflammatory pain, in part by sensitizing afferent nerve fibers, and expression of NGF is increased during bladder inflammation. We investigated whether intravesical instillation of the selective cannabinoid receptor 1 (CB1) agonist arachidonyl-2'-chloroethylamide (ACEA) affects NGF-induced increased bladder activity in female C57BL/6J wild-type (WT) mice. We also examined the effects of intravesical NGF in female fatty acid amide hydrolase knock-out (FAAH KO) mice. ⋯ The inhibitory effects of ACEA were reversed by the selective CB1 antagonist AM 251. Intravesical NGF failed to affect bladder activity in FAAH KO mice, and treatment with AM251, restored the stimulatory effects of NGF on the bladder in FAAH KO mice. These results indicate that activation of CB1 inhibits increased bladder activity induced by NGF.
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Neuroscience letters · Mar 2015
Possible involvement of activated locus coeruleus-noradrenergic neurons in pain-related sleep disorders.
The locus coeruleus (LC) is a noradrenergic brainstem structure that is considered to play a role in promoting arousal. To further clarify the role of LC noradrenergic neurons, we performed an optogenetic assay by injecting AAV-channelrhodopsin-2 (ChR2) into the LC of cre-tyrosine hydrolase (TH) mice. We found here that the specific activation of LC noradrenergic neurons produced a significant increase in wakefulness and a significant decrease in non-rapid eye movement (NREM) sleep during photostimulation. ⋯ In the present study, sciatic nerve ligation, which produced significant thermal hyperalgesia, significantly increased the levels of noradrenaline released in the prefrontal cortex (PFC) by the weak electrical stimulation of neurons in the LC. Under these conditions, the systemic administration of adrenaline α and β inhibitor cocktail at 7 days after sciatic nerve ligation restored the increased wakefulness and decreased NREM sleep to normal levels. These results suggest that neuropathic pain may accelerate neurons in the LC, and its overactivation may be, at least in part, associated with sleep disturbance under neuropathic pain.
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Neuroscience letters · Mar 2015
A new rat model of neuropathic pain: complete brachial plexus avulsion.
Brachial plexus avulsion (BPA) is one of the major injuries in motor vehicle accidents and may result in neuropathic pain. Accumulating evidence suggests that 30-80% of BPA developed neuropathic pain in human. ⋯ Complete brachial plexus avulsion mimics human nerve root traction injury following traffic accidents. The complete BPA rat model approach human injuries and can be used for further investigations.
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Neuroscience letters · Feb 2015
Meta AnalysisVoxelwise meta-analysis of gray matter anomalies in Parkinson variant of multiple system atrophy and Parkinson's disease using anatomic likelihood estimation.
Numerous voxel-based morphometry (VBM) studies on gray matter (GM) in patients with the Parkinson variant of multiple system atrophy (MSA-P) and Parkinson's disease (PD) have been separately conducted. Identifying the different neuroanatomical changes in GM between MSA-P and PD through meta-analysis may aid the differential diagnosis of MSA-P and PD. A systematic review of VBM studies on patients with MSA-P and PD compared to healthy controls (HC) from the PubMed and Embase databases between January 1995 and June 2014 was conducted. ⋯ For patients with disease duration within 5 years, compared with PD, the decrease in GMV focused on the bilateral putamen and claustrum in MSA-P. In contrast, for patients with disease duration within 3 years, no significant GMV difference was found between MSA-P and PD. Our meta-analysis indicated that the atrophy of bilateral putamen or claustrum is not a neuroanatomical marker for distinguishing MSA-P from PD during the early stage by using the VBM method.
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Neuroscience letters · Feb 2015
Intrathecal nefopam-induced antinociception through activation of descending serotonergic projections involving spinal 5-HT7 but not 5-HT3 receptors.
We examined the involvement of spinal 5-HT(5-hydroxytryptamine) receptor 3(5-HT3R) and 7(5-HT7R) as well as the overall role of descending serotonergic projections in the analgesic effects of intrathecal(i.t.) nefopam for two rat models of formalin and paw incision test. I.t. nefopam produced an antinociceptive effect in a dose-dependent manner in both tests. Lesioning the spinal serotonergic projections using i.t. 5,7-dihydroxytryptamine(5,7-DHT) did not influence the intensity of allodynia in the paw incision test, but i.t. 5,7-DHT abolished the effect of nefopam. ⋯ Antagonism study showed that i.t. 5-HT7R antagonist, SB269970 significantly blocked the antinociceptive effect of nefopam in both tests, but i.t. 5-HT3R antagonist, ondansetron has no influence on the effect of nefopam. The present study demonstrates that descending spinal serotonergic projections play a vital role in antinociceptive effect of i.t. nefopam in the paw incision test, but indeterminate in the formalin test. In both tests, the antinociceptive effect of i.t. nefopam involves the spinal 5-HT7R, but not 5-HT3R.