Effect on Microphonics of Acetylcholine Injected Into the Endolymphatic Space

Abstract

Martini (1940) claimed that acetylcholine can be demonstrated in the perilymph on sound stimulation of the inner ear. However, neither in the perilymph nor in the endolymph could Gisselsson (1950) show any acetylcholine during or after sound stimulation. On the other hand, he found abundant acetylcholinesterase in the endolymph and showed that intraarterial injection of acetylcholinesterase inhibitor into the cat and the guinea-pig interfered with the generation of microphonics. Injection of acetylcholine had no demonstrable effect on the microphonic potentials. Using Koelle's histochemical method Churchill, Schuhknecht & Doran (1956) demonstrated the presence of acetylcholinesterase in the nerve fibres located within and near the organ of Corti.