Histochemical localization of adenylate cyclase and phosphodiesterase activities in the foliate papillae of the rabbit. II. Electron microscopic observations

Adenylate cyclase and cyclic AMP phosphodiesterase activities in the foliate papillae of rabbit were studied by means of electron microscopic histochemistry using slightly modified procedures of Howell and Whitfield (1972) and Florendo et al . (1971), respectively. The reaction products of both the enzyme activities were localized on the surface membrane of the microvilli of the type I taste bud cells (dark cells). The results suggest that a cyclic nucleotide system is involved in the transduction process of taste organs.