Antagonism by dopamine, but not noradrenaline receptor blockers of the anti-immobility activity of desipramine after different treatment schedules in the rat.

The effect of antidopaminergic and antiadrenergic agents on the anti-immobility activity of desipramine after different schedules of treatment was studied in rats. 0.5 mg/kg i.p. haloperidol and 100 mg/kg i.p. sulpiride antagonized the anti-immobility effect of three injections of 10 mg/kg desipramine. Similar results were obtained after 7 or 21 daily doses of 10 mg/kg desipramine. Neither 5 mg/kg i.p. propranolol nor 3 mg/kg s.c. prazosin had any effect on desipramine after the various treatment schedules. It is suggested that DA mechanisms are involved in the anti-immobility effect of repeated desipramine in the rat. A possible role of beta-adrenergic receptors in the development of this effect is discussed.