Purinoceptor-mediated, Capsaicin-resistant Excitatory Effect of Allyl Isothiocyanate on Neurons of the Guinea-Pig Small Intestine

Abstract

Allyl isothiocyanate (AITC; 200μM) caused atropine- and tetrodotoxin-sensitive longitudinal muscle contraction on the guinea-pig small intestine. The response was not influenced by hexamethonium, a functional blockade of capsaicin-sensitive neurons or by antagonists acting at TRPV1 or TRPA1, but was abolished by the P2 purinoceptor antagonist PPADS (50μM). It is concluded that cholinergic motoneurons are activated by a purinergic mechanism in the course of the AITC response, independently of capsaicin-sensitive processes or even TRPA1.