In situ discharge response of oral arms elicited by combined chemical-mechanical stimulation with the chemosensitizer compound glutamate (10−3 M) combined alternatively to 70% v/v ethanol, 20% v/v ammonia or 5% v/v acetic acid was also dramatically impaired with respect to that observed following combined chemical-mechanical stimulation with glutamate alone (p < 0.001, Fig. 3).