Abstract: A neuropharmacological study was undertaken in the cat to obtain further evidence of the role of acetylcholine in vestibular function. It was shown that the vestibular nerve contains about half or less the enzymatic activity of choline acetyltransferase. acetylcholinesterase, cholinesterase and total cholinesterase than nucleus vestibularis lateralis (NVL).Field potentials as well as discharge of single neurones of nucleus vestibularis lateralis (NVL) were studied in locally anaesthetized, decamethonium immobilized ventilated cats before, during and after vestibular nerve and reticular formation stimulation. Various cholinergic agonists and antagonists and the adrenergic agonists l-DOPA and (+)-amphetamine were then given intravenously to determine their effects. Three major evoked potentials to vestibular nerve stimulation were recorded in NVL. These potentials were labelled N1, N2and N3 on the basis of polarity and latency. Although the N1 and N3 waves were not much affected, the N3 wave was dramatically enhanced by physostigmine and reduced by scopolamine.About half of NVL neurones excited by vestibular nerve stimulation responded to muscarinic cholinergic drugs. Nucleus vestibularis lateralis responses to reticular formation (RF) stimulation were primarily nicotinic and were blocked by the nicotinic antagonist, mecamylamine, but not trimethadinium. Some neurones excited by RF stimulation were enhanced by l-DOPA or (+)-amphetamine. The data indicate that cholinergic mechanisms are strongly involved in vestibular function. Adrenergic mechanisms are also involved, but to a much lesser extent.

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   |wiki=    Wicri/Lorraine
   |area=    LrgpV1
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   |clé=     ISTEX:66AC890E2DF6DE0ABB2AE7872CC9F86F6658765B
   |texte=   Cholinergic mechanisms in the cat vestibular system
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