Effects of halopemide on potassium-induced release of radiolabeled neurotransmitters from rat cerebrocortical slices in vitro.

The effects of halopemide on the release of 3H-serotonin, 3H-noradrenaline, 3H-acetylcholine and 3H-GABA from rat frontal cortical slices in vitro were studied and compared to those of its neuroleptic congener R29800, spiperone and haloperidol. Spontaneous 3H-serotonin and to a lesser extend 3H-noradrenaline outflow were augmented by the agents, while the effects on basal 3H-acetylcholine and 3H-GABA release were small or absent. Mechanism explaining these effects are discussed. Depolarization-induced release of serotonin was affected more markedly than the extra overflow of other radiolabeled transmitters, but the statistical significant of the response was limited.