Neuropharmacological and behavioural properties of remoxipride in the rat

Remoxipride blocks dopamine agonist-induced effects in the rat, mediated by dopamine D2 receptors with an in-vivo potency less than that of haloperidol but greater than that of chlorpromazine, thioridazine, and sulpiride. Unlike haloperidol and sulpiride, remoxipride has weaker antagonistic effects towards presynaptic dopamine activity compared to its effects on postsynaptically mediated activity. Remoxipride causes a preferential inhibition of dopamine agonist-induced locomotion as compared to stereotyped behaviour, suggesting that it may exert a preferential blockade of mesolimbic dopamine neurotransmission. The low tendency of remoxipride to cause catalepsy in the rat is indicative of a weak effect on striatal dopamine neurotransmission and predicts a low liability to induce extrapyramidal side effects in man. Remoxipride causes a smaller elevation of prolactin than sulpiride at doses producing central dopamine receptor blockade. The results suggest that remoxipride, unlike haloperidol, can discriminate between different types of dopamine mediated functions probably by having a preferential action on subpopulations of functionally coupled dopamine D2 receptors.