Neurotoxicology
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Administration of chemotherapy during the fetal phase of pregnancy may put late-developing organs like the central nervous system at risk. ⋯ The current preclinical data reveal subtle changes in behaviour and transiently also in brain morphology in the mice that were prenatally exposed to vinblastine or doxorubicin.
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Riluzole has been shown to possess neuroprotective effects in a variety of neurological and animal model of diseases, including motor diseases. However, the mechanism(s) by which riluzole preserves the intrinsic electrophysiological characteristics of neuronal membrane has not been fully delineated. Ataxia is a clinical manifestation of disturbance in coordinated motor activity, which may be caused by cerebellar impairment. ⋯ The normal firing behaviour and action potential characteristics of Purkinje neurones were preserved. The amplitude of both fast after hyperpolarization potential (fAHP) and post train after hyperpolarization potential, a marker of slow AHP (sAHP), along with the duration of post train AHP, which play an important role in regulating the firing behaviour were restored to the control conditions. These findings suggest that riluzole-induced neuroprotection may be mediated at least in part by activation of Ca(2+)-dependent K(+) channel function.
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Ketamine, a non-competitive N-methyl-d-aspartate (NMDA) receptor antagonist, is used as a pediatric anesthetic for surgical procedures. Recent data suggest that anesthetic drugs may cause neurodegeneration during development. The purpose of this study was to determine the dose and temporal response of ketamine using newborn rat forebrain cultures and also to determine if co-administration of 7-nitroindazole, a nitric oxide synthase (NOS) inhibitor, could protect or reverse ketamine-induced cell death. ⋯ No significant effect was observed in the release of lactate dehydrogenase (LDH). Ketamine-induced neurotoxic effects were effectively blocked by 7-nitroindazole (10 microM). These data indicate a role for nitric oxide in the enhanced degeneration induced by ketamine in vitro and also suggest that blocking neuronal nitric oxide synthase (nNOS) may help reduce the risk of ketamine in pediatrics.
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Paclitaxel-induced sensory neuropathy is a problematic side-effect of cancer chemotherapy. Previous studies in rodents have shown paclitaxel treatment to have many effects on different parts of the peripheral nervous system, but those responsible for its bothersome clinical side-effects are still unclear. In the current study, we sought to obtain information about the involvement of sensory neurons in paclitaxel neurotoxicity at the level of the dorsal root ganglion. ⋯ In the L5 dorsal root ganglion, nucleolus size and the number of neurons with eccentric nuclei were increased only in a subpopulation of dorsal root ganglion neurons with cell body cross-sectional areas greater than 1750 microm(2), which made up less than 10% of the total population. Paclitaxel treatment increased immunohistochemical staining for activating transcription factor-3 (ATF-3), c-Jun and neuropeptide Y (NPY) but only in a small percentage of neuronal cell bodies and mainly in those with large cell bodies. In conclusion, we have demonstrated that nucleolar enlargement, nuclear eccentricity, ATF-3, c-Jun and NPY are neuronal markers of paclitaxel-induced sensory neuropathy, however, these axotomy-like cell body reactions are infrequent and occur in mainly large-sized sensory neurons.
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Citalopram is a very potent and highly selective inhibitor of neuronal serotonin (5-hydroxytryptamine, or 5-HT). Serotonin syndrome is a rarely observed side-effect of Citalopram use. This report discusses a case of first time, low dose citalopram use-related serotonin syndrome presenting with confusion, hyperhidrosis, hyperreflexia, myoclonus and fever.