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 exposure was analyzed using high-performance liquid chromatography coupled with electrochemical detection. Animals were exposed for 1 h to white 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, noise stimulation resulted in a progressive decrease of cochlear DA concentration. This decrease was scarcely detected when animals were pretreated with piribedil. Present findings indicate that piribedil modifies cochlear DA turnover under noise stimulation.