Brain research
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The subventricular zone (SVZ) of the adult mouse brain retains the capacity to generate new neurons from stem cells. The neuronal precursors migrate tangentially along the rostral migratory stream (RMS) towards the olfactory bulb, where they differentiate as periglomerular and granular interneurons. In this study, we have investigated whether nitric oxide (NO), a signaling molecule in the nervous system with a role in embryonic neurogenesis, may be produced in the proximity of the progenitor cells in the adult brain, as a prerequisite to proposing a functional role for NO in adult neurogenesis. ⋯ Within the olfactory bulb, many small cells in the granular layer and around the glomeruli expressed either PSA-NCAM or NOS I and, in some cases, both markers. Colocalization was also found in a few isolated cells at a certain distance from the neurogenesis areas. The anatomical disposition shown indicates that NO may be released close enough to the neuronal progenitors to allow a functional influence of this messenger in adult neurogenesis.
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Cessation of ethanol administration in ethanol-dependent rats results in an ethanol withdrawal (ETX) syndrome, including audiogenic seizures (AGS). The inferior colliculus (IC) is the initiation site for AGS, and membrane properties of IC neurons exhibit hyperexcitability during ETX. Previous studies observed that ETX alters GABA and glutamate neurotransmission in certain brain sites. ⋯ However, IPSPs during ETX displayed a significantly greater sensitivity to bicuculline. These data indicate that decreased GABA(A)-mediated inhibition and increased glutamate-mediated excitability in IC may both be critical mechanisms of AGS initiation during ETX, which is similar to observations in a genetic form of AGS. The common changes in IC neurotransmission in these AGS forms may be general mechanisms subserving AGS and other forms of auditory system pathophysiology in which the IC is implicated.