Neuroscience letters
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Neuroscience letters · May 2007
[3H] pregabalin binding is increased in ipsilateral dorsal horn following chronic constriction injury.
Pregabalin, a 3-substituted analogue of gamma-amino butyric acid has recently been approved for treatment of neuropathic pain. We have investigated the anatomical binding profile of [(3)H] pregabalin following chronic constriction injury (CCI) and compared this with alpha 2 delta 1 subunit expression using in situ hybridisation. ⋯ The increased expression of calcium channel subunits and protein in central terminals is interesting, given that abnormal activity within sensory nerves is likely to significantly contribute to the symptomatology of neuropathic pain. The upregulation of pregabalin binding sites in sensory nerve terminals may occur as part of the response to nerve damage in neuropathic pain patients, and therefore, preferential actions of pregabalin at these sites may contribute to its mechanism of action in man.
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Neuroscience letters · Apr 2007
Inhibitory action of protein kinase Cbeta inhibitor on tetrodotoxin-resistant Na+ current in small dorsal root ganglion neurons in diabetic rats.
Experimental evidence has been presented to suggest that protein kinase Cbeta isoform-selective inhibitor LY333531 is effective at alleviating diabetic hyperalgesia. In the present study, we isolated small (< or =25 microm in soma diameter) dorsal root ganglion (DRG) neurons from control and streptozocin (STZ)-induced diabetic rats, and examined the acute action of LY333531 (1-1000 nM) on the tetrodotoxin-resistant Na(+) current (TTX-R I(Na)), which plays an essential role in transmitting nociceptive impulses, using the whole-cell patch-clamp method. ⋯ Thus, TTX-R I(Na), which is upregulated in the diabetic state, is likely to be more potently inhibited by submicromolar concentrations of LY333531. These results suggest that an acute inhibition of TTX-R I(Na) by LY333531 attenuates the exaggerated excitability of DRG neurons in the diabetic state, which appears to be related at least partly to anti-hyperalgesic actions of the drug in diabetic neuropathy.
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Neuroscience letters · Apr 2007
Significant correlation between plasma and CSF anticholinergic activity in presurgical patients.
Previous studies have suggested a possible link between cognitive impairment and anticholinergic burden as reflected by high serum anticholinergic activity (SAA). Thus, we hypothesized a close relationship between anticholinergic activity in cerebral spinal fluid (CSF) and blood. However, it has never been convincingly demonstrated that peripheral anticholinergic activity correlates with central anticholinergic levels in presurgical patients. ⋯ A significant linear correlation was detected between blood and CSF levels. Therefore we conclude that SAA levels adequately reflect central anticholinergic activity. When patients receiving or not receiving anticholinergic medication were compared, anticholinergic activity tended to increase in blood and CSF after receiving anticholinergic medication > or =4 weeks (p>0.05).
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Neuroscience letters · Apr 2007
Olfactory ensheathing cells exert a trophic effect on the hypothalamic neurons in vitro.
Olfactory ensheathing cells (OECs) constitute an usual population of glial cells sharing properties with both Schwann cells (SC) of peripheral nervous system (PNS) and astrocytes of the central nervous system (CNS). They express a high level of growth factors which play a very important role as neuronal support. Recent evidence in literature suggests that OECs may facilitate axonal regeneration in the injured nervous system. ⋯ Moreover, we show that NGF promoted a major neuronal survival than bFGF and GDNF, while bFGF and GDNF exerted an evidence axonal and dendritic outgrowth compared to NGF. In conclusion, these data suggest that OECs have the capacity to promote the survival and axonal outgrowth of hypothalamic neurons in vitro and that bFGF, NGF and GDNF differentially support hypothalamic neurons promoting and enhancing the neuronal survival and outgrowth. Therefore, the OECs are a source of growth factors and might be considered a better approach for functional recovery and growth factors might exert a neuroprotective effect in neurodegenerative disorders.
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Neuroscience letters · Apr 2007
Etomidate and propofol-hyposensitive GABAA receptor beta3(N265M) mice show little changes in acute alcohol sensitivity but enhanced tolerance and withdrawal.
Gamma-aminobutyric acid-A (GABAA) receptors are ligand-gated ion channels comprised of subunits from several classes (alpha, beta, gamma, delta). Recent studies have clearly demonstrated that the functional properties of GABAA receptors are altered following chronic ethanol administration that could provide the molecular basis for the previously proposed role of these receptors in ethanol tolerance and dependence. Because the subunit composition of GABAA receptors determines receptor pharmacology, the present study was devoted to assess if the behavioral sensitivity after acute and chronic ethanol exposure depends on beta3-containing GABAA receptors. ⋯ However, following repeated LORR testing, enhanced tolerance to the intoxicating effects of ethanol was observed--a finding which was unrelated to the pharmacokinetics of ethanol as both genotypes had the same blood alcohol concentrations following repeated LORR testing. In addition, following chronic alcohol vapor exposure, mouse mutants displayed increased handling-induced convulsions during withdrawal. The results of the present study suggest that the alcohol effects abolished by the beta3(N265M) mutation do not play a dominant role in acute alcohol intoxication but influence ethanol tolerance and withdrawal.