Experimental evaluation of the antidepressant and neuroleptic activity of maprotiline.

Maprotiline, a tetracyclic antidepressant drug, was evaluated for antidepressant and neuroleptic activity. In antidepressant tests, maprotiline antagonized reserpine-induced ptosis in rats but, unlike the tricyclic antidepressants, was found to antagonize methamphetamine stereotypy in rats, to decrease the intensity of L-dopa induced behavioural syndrome in pargyline-pretreated mice and to be ineffective in intensifying the 5-HTP induced behavioural syndrome. In neuroleptic tests, maprotiline was found to, antagonize apomorphine-induced cage climbing behaviour, induce catalepsy, inhibit the CAR and traction response, decrease the spontaneous motor activity and exploratory behaviour, and to potentiate the hypnotic effect of pentobarbitone. Our results indicate that maprotiline exhibits a profile of activity which resembles the neuroleptics and most probably exerts post-synaptic striatal DA receptor blocking activity.

Blockade of the dopamine depressor response by molindone, a newly introduced neuroleptic.

Pretreatment with the neuroleptics, haloperidol and molindone, significantly antagonized the dopamine-induced depressor response in the anaesthetized dogs. The depressor response to dopamine was however, not significantly affected by propranolol, atropine or antazoline pretreatment. The results suggest that molindone like haloperidol, is capable of blocking the vascular dopamine receptors responsible for mediating dopamine-induced vasodilatation in the coeliac, mesenteric and renal vascular bed and fall in blood pressure.