Linalool modifies the nicotinic receptor-ion channel kinetics at the mouseneuromuscular junction

Linalool is a monoterpene compound reported to be a major component of esse ntial oils in various aromatic species. Several linalool-producing species are used in traditional medical systems. Among these is Aeolanthus suaveole ns G. Dom (Labiatae) which is used as an anticonvulsant in the Brazilian Am azon. Psychopharmacological in vivo evaluation of linalool showed that this compound has dose-dependent marked sedative effects at the central nervous system (CNS), including hypnotic, anticonvulsant and hypothermic propertie s. It has been suggested that these neurochemical effects might be ascribed to the local anaesthetic activity of linalool. The present study reports a n inhibitory effect of linalool on the acetylcholine (ACh) release and on t he channel open time in the mouse neuromuscular junction. These findings co uld provide a rational basis to confirm the traditional medical use of lina lool-producing plant species. Indeed,our data demonstrate some interactions in the modulation of the ACh release at the mouse neuromuscular junction, which are well correlated with the suggested molecular mechanisms. Linalool induced a reduction of the ACh-evoked release. The possibility that this e ffect could be ascribed to some interaction with pre-synaptic function is n oteworthy. Moreover, the inhibitory effect induced on the kinetics of the m iniature end-plate current decay demonstrates a local anaesthetic action, e ither on the voltage or on the receptor-activated channels. (C) 2000 Academ ic Press.