RELEASE OF [3H]SEROTONIN FROM BRAIN SLICES

1. Labelled serotonin ([3H]5‐HT) accumulated by slices of rat brain either in vivo or in vitro is released by depolarizing procedures such as electrical stimulation or high external potassium concentrations. Electrical stimulation predominantly affects the liberation of the unchanged amine, rather than of its principal metabolite, 5‐HIAA. 2. Release of [3H]5‐HT does not appear to be calcium‐dependent. 3. Amount of release parallels the density of serotonin‐containing nerve terminals in each of several cerebral regions tested. Release from several extracerebral tissues was similar to that obtained from cerebral tissues having relatively little endogenous 5‐HT. 4. Electrically induced release of [3H]5‐HT is markedly inhibited by desipramine, chlorpromazine, LSD, lithium and ouabain. Copyright © 1969, Wiley Blackwell. All rights reserved