"In vivo" release of endogenous neurotransmitters in cat limbic regions: effect of chlorpromazine and of electrical stimulation.

The effect of chlorpromazine (10 mg/kg i.v.) on the spontaneous release of endogenous dopamine (DA), noradrenaline (NA) and acetylcholine (ACh) within limbic areas perfused by means of the push-pull cannula was investigated in the gallamine-immobilized cat. Chlorpromazine increased the liberation of DA and NA in the nucleus accumbens septi, indicating blockade of the amine receptors. However, the drug did not change the output of ACh from this nucleus nor from ventral and dorsal hippocampal formations which receive a cholinergic input from the septum as indicated by several published findings and by the increased liberation of ACh after electrical stimulation of the homolateral nucleus medialis septi. These results seem to exclude that cholinergic neurons of some limbic areas mediate the effect of the blockade of DA (and of NA) receptors which is possibly involved in the antipsychotic action of neuroleptic drugs.