PIRIBEDIL COULD MODIFY DOPAMINE TURNOVER IN COCHLEAS UNDER NOISE STIMULATION

Dopamine (DA) is one of the putative neurotransmitters of the lateral efferent olivocochlear fibers. The cochlear DA content after noise exp osure was analyzed using high-performance liquid chromatography couple d with electrochemical detection. Animals were exposed for 1 h to whit e noise at 70, 90 or 110 dB SPL or were kept in conditions of silence. Half of the animals were pretreated with piribedil, a D2 agonist, and the other half served as controls. In control (untreated) animals, no ise stimulation resulted in a progressive decrease of cochlear DA conc entration. This decrease was scarcely detected when animals were pretr eated with piribedil. Present findings indicate that piribedil modifie s cochlear DA turnover under noise stimulation