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Title

Medial vestibular nucleus in the guinea-pig: NMDA-induced oscillations

Authors
Khateb, A.
de Waele, C.
Vidal, P. P.
Published in Experimental Brain Research. 1992, vol. 88, no. 1, p. 187-192
Abstract We have recently shown in vivo that N-Methyl-D-Aspartate (NMDA) receptors are present in the guinea-pig vestibular complex and demonstrated that they are involved in the regulation of the resting discharge of vestibular neurones. A parallel in vitro study has identified in the guinea-pig medial vestibular nuclei (MVN) two main neuronal cell types, A and B MVNn, differing by their intrinsic membrane properties. One subtype of B MVNn was further characterized by the presence of a low threshold calcium spike (LTS). The present study investigated in vitro the responses of these different cell types to NMDA. Both A and B MVNn were depolarized by NMDA, which also induced a decrease in membrane resistance and an increase in the spontaneous firing rate. These effects could be blocked by D-AP5, a specific antagonist of NMDA receptors. Following a 10-30 mV hyperpolarization, a long-lasting oscillatory behavior could be induced in presence of NMDA. These oscillations were however restricted to the subtype of B MVNn without LTS. The NMDA-induced oscillations were tetrodotoxine-resistant, but could be eliminated by D-AP5 or by replacing sodium with choline. Functional implications of this oscillatory behavior are discussed.
Keywords AnimalsBrain Stem/ physiologyCerebral Ventricles/ physiologyCholine/pharmacologyElectric Conductivity/drug effectsEvoked Potentials/drug effectsGuinea PigsN-Methylaspartate/ pharmacologyNeurons/drug effects/ physiologySodium/pharmacologyTetrodotoxin/pharmacology
Stable URL http://archive-ouverte.unige.ch/unige:10126
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PMID: 1347271
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