TAURINE ENTRY INTO PERILYMPH OF THE GUINEA-PIG

Taurine is a beta-aminosulfonic acid and is a ubiquitous amino acid wh ose role in the cochlea is not well established. In this study, its en try from blood into perilymph was investigated in the guinea pig as an imal model. The penetration rate of [H-3]taurine (molecular weight 125 ) into the perilymph of the scala vestibuli was measured 1 and 2 h aft er the intravenous infusion of [H-3]taurine in nephrectomized animals. Results showed a rate of penetration in perilymph related to plasma a t 36 +/- 4.7% (n = 5) after 1 h and 43 +/- 5.6% (n = 5) after 2 h. Com pared to the penetration rate of urea (molecular weight 60) and mannit ol (molecular weight 186) reported previously in rats, a passive entry of taurine into perilymph through the blood-perilymph barrier is sugg ested.