THE TASTE OF ETHANOL IN A PRIMATE MODEL .1. CHORDA TYMPANI NERVE RESPONSE IN MACACA-MULATTA

The chorda tympani nerve (CT) mediates taste from the anterior part of the tongue. Here we studied the effects of ethanol on the tongue in r ecordings from both the whole CT nerve and individual taste fibers of the rhesus monkey, M. mulatta. The response to ethanol consisted of a phasic and a tonic part. At the lowest concentration tested (0.3 M) et hanol gave a response in some animals and at 0.7 M in all animals. A s igmoidal function described best the relationship between nerve respon se and ethanol concentrations. Hierarchial duster analysis with 26 non alcoholic sweet, sour, salty, and bitter stimuli had earlier identifie d four types of taste fibers each responding predominantly to stimuli within one of the four human taste qualities. Here we found that ethan ol stimulated all sweet-best fibers and at high concentration some sal t-best fibers, but never any acid-best and bitter-best fibers. This ma y explain the sweet taste attributed to low ethanol concentration by h umans. Further, in mixtures it suppressed the responses in acid-best a nd bitter-best taste fibers. This may partly explain the effects of et hanol on sour and bitter taste in alcoholic beverages. (C) 1997 Elsevi er Science Inc.