Neuroscience letters
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Neuroscience letters · May 2014
Myelinated Ah-type trigeminal ganglion neurons in female rats: neuroexcitability, chemosensitivity to histamine, and potential clinical impact.
Migraine is a chronic neurological disorder characterized by recurrent moderate-to-severe headaches often associated with numerous autonomic nervous system symptoms, and it is more prevalent in women. To fully understand the underlying mechanism, standard electrophysiology was performed with trigeminal ganglion neurons (TGNs) isolated from adult rats of both genders using the whole-cell patch clamp technique to test the distribution, neuroexcitability, and chemosensitivity to histamine. In addition to traditionally classified A- and C-type TGNs, myelinated Ah-type TGNs were also observed in females. ⋯ Iberiotoxin and NS11021 significantly altered the discharge profiles of Ah-type TGNs. Finally, Ah-type TGNs showed a more potent reaction to histamine, with relatively larger inward currents and membrane depolarization compared with C-types. These data provide evidence of the gender-specific distribution of myelinated Ah-type TGNs in adult female rats, characterized by a low threshold and high frequency of firing that are at least partially attributable to persistent TTX-R Na(+) and BK-KCa channel expression and potent chemosensitivity to histamine, suggesting that Ah-type TGNs may play a key role in gender differences in migraine.
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Neuroscience letters · May 2014
Metabotropic glutamate receptors regulate cortical gamma hyperactivities elicited by ketamine in rats.
Abnormalities in electroencephalogram gamma oscillations have been implicated in schizophrenic symptoms. N-methyl-d-aspartate (NMDA) receptor antagonists produce behavioral abnormalities that are similar to the symptoms of schizophrenia, including social and cognitive impairment, and also increase the power of spontaneous gamma oscillations in the frontal cortex in rodents. Both mGlu2/3 receptor agonists and mGlu1 receptor antagonists reportedly improve behavioral abnormalities elicited by NMDA receptor antagonists in rodents. ⋯ Ketamine increased spontaneous cortical gamma oscillations. Pretreatment with an mGlu2/3 receptor agonist, (-)-2-oxa-4-aminobicyclo[3.1.0]hexane-4,6-dicarboxylate (LY379268), or an mGlu1 receptor antagonist, (3,4-dihydro-2H-pyrano[2,3-b]quinolin-7-yl)-(cis-4-methoxycyclohexyl)-methanone (JNJ16259685), reduced the ketamine-induced basal gamma hyperactivity. These findings indicate that the stimulation of mGlu2/3 receptors and the inhibition of mGlu1 receptors reverse aberrant gamma oscillations, and these effects may partially explain the antipsychotic-like properties of mGlu2/3 receptor agonists and mGlu1 receptor antagonists.
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Neuroscience letters · Apr 2014
Randomized Controlled TrialEffect of handball training on cognitive ability in elderly with mild cognitive impairment.
The aim was to examine the effect of handball training on cognitive ability in elderly with mild cognitive impairment. A total of 60 elderly were randomly divided into training group (n=30) and control group (n=30). ⋯ The results showed that MMSE score was increased and ADL score was decreased in training group after 3-month and 6-month intervention (P<0.05), while there were no significant changes in MMSE or ADL in control group (P£3/40.05). These preliminary results indicated that handball training can improve cognitive ability in elderly with MCI.
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Neuroscience letters · Apr 2014
Suppression of spinal connexin 43 expression attenuates mechanical hypersensitivity in rats after an L5 spinal nerve injury.
Activation of spinal astrocytes may contribute to neuropathic pain. Adjacent astrocytes can make direct communication through gap junctions formed by connexin 43 (Cx43) in the central nervous system. Yet, the role of spinal astroglial gap junctions in neuropathic pain is not fully understood. ⋯ Western blot analysis and immunohistochemistry also showed that SNL increased GFAP expression, but decreased Cx43 expression, in spinal cord. Our results provide direct evidence that selective suppression of spinal Cx43 after nerve injury alleviates neuropathic mechanical hypersensitivity. These findings suggest that in the spinal cord, the enhanced function of astroglial gap junctions, especially those formed by Cx43, may be important to neuropathic pain in SNL rats.
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Neuroscience letters · Apr 2014
Role of the 5-HT(7) receptor in the effects of intrathecal nefopam in neuropathic pain in rats.
Nefopam is a non-opioid analgesic drug, used widely in European countries to control postoperative pain. However, its mechanism of action remains unclear. In this study, the effects of intrathecal nefopam on spinal nerve-ligated induced neuropathic pain in rats were examined and the involvement of the 5-HT7 receptor at the spinal level was determined. ⋯ Intrathecal nefopam increased the levels of 5-HT in the spinal cord and plasma. Intrathecal nefopam is effective in the attenuation of neuropathic pain induced by spinal nerve ligation and nefopam increases the level of 5-HT. Additionally, the 5-HT7 receptor is involved in the antiallodynic action of nefopam in the spinal cord.