Release of labelled taurine from the rat dorsal medulla and cerebellum in vivo.

Stimulus-induced release of labelled taurine has been studied in the superfused rat cerebellar cortex and dorsal medulla in vivo. In the cerebellum both elevated potassium and electrically induced depolarization consistently produced marked increases in the efflux of exogenously applied taurine in a calcium-dependent fashion. Veratridine-stimulation evoked a large Ca2+-independent taurine efflux which was, however, prevented by tetrodotoxin. In the dorsal medulla, both high K+ and veratridine induced a clear Ca2+-independent increase in taurine efflux. Electrical stimulation was always ineffective in changing taurine efflux from the dorsal medulla. These data strongly support a possible neurohumoral role for taurine in the cerebellum but not in the dorsal medulla.