Afferent and Efferent Nerve Terminal Degeneration in the Guinea-Pig Cochlea Following Atoxyl Administration

Abstract

Atoxyl causes destruction of both afferent and efferent nerve endings. Degeneration of afferent nerve terminals occurred even though the adjacent hair cell had a normal ultrastructure. The degeneration of the efferent nerve endings took place at the same time as the adjacent cell disintegration. Earlier studies on the effects of atoxyl have shown that it also induces damage to the stria vas-cularis and Reissner's membrane, thus interfering with endolymph metabolism (Anniko & Wersäll, 1975; Anniko, 1975 a, b). The afferent nerve terminals may be more sensitive to changes in the environment (endolymph) than are the surrounding structures, including efferent nerve endings, hair cells and supporting structures, and would therefore be the first structures to disintegrate.