Endogenous serotonin release from rat cerebellar slices

1. 1. Endogenous serotonin (5-HT) content in cerebellar slices and in the incubation medium was measured before and after depolarizing stimulus with high-K+ concentration in the medium. 2. 2. Small amount of 5-HT was spontaneously released from tissue slices incubated in low-K+ and Ca2+-free medium. 3. 3. A significant increase of endogenous 5-HT release was obtained after depolarizing stimulus with high-K+ plus Ca2+ in the medium. 4. 4. It is suggested that the endogenous 5-HT release in cerebellum induced by depolarizing stimuli is a Ca2+-dependent phenomenon. © 1987