EFFECT OF REPEATED TREATMENT WITH DESIPRAMINE IN THE BEHAVIORAL DESPAIR TEST IN RATS - ANTAGONISM BY ATYPICAL BUT NOT CLASSICAL NEUROLEPTICS OR ANTIADRENERGIC DRUGS

A 7-day treatment with 20 mg/kg per day desipramine [DMI] reduced the immobility time in the behavioral despair test in rats. The effect of DMI was antagonized by sulpiride (100 mg/kg i.p.), metoclopramide (20 mg/kg i.p.) and clopazine (20 mg/kg i.p.) but not by haloperidol (0.5 mg/kg i.p.) or chlorpromazine (5 mg/kg i.p.). .alpha.-Adrenoreceptor blockers (prazosin 3 mg/kg s.c.; aceperone 10 mg/kg i.p.; azapetine 24 mg/kg s.c.; phentolamine 20 mg/kg i.p.), dl-propranolol (5 mg/kg i.p.) and clonidine (0.1 mg/kg i.p.) failed to modify the anti-immobility effect of DMI. Apparently, a particular subtype of dopamine receptors is involved in the anti-immobility effect of a 7-day treatment with DMI in the behavioral despair test in rats.