Putative interaction of presynaptic dopamine and serotonin receptors modulating synaptosomal tyrosine hydroxylase activity in the nucleus accumbens of rats.

Inhibition of synaptosomal tyrosine hydroxylase activity by dopamine (DA) autoreceptors and serotonin (5-HT) heteroreceptors was used as a functional measure for the receptor activity in the nucleus accumbens of rats. Kinetic analysis of the concentration dependence of inhibition with and without antagonists indicates that the sensitivity of the autoreceptor to DA is significantly increased by blockade of the 5-HT heteroreceptor and vice versa. The results provide evidence for autoreceptor-heteroreceptor interactions at the presynaptic membrane level on dopaminergic nerve terminals.