Desipramine given repeatedly enhances behavioural effects of dopamine and d-amphetamine injected into the nucleus accumbens.

The effect of desipramine (DMI) was studied after its repeated administration (10 mg/kg p.o., twice daily, 14 days) to rats, on the action of dopamine and d-amphetamine injected bilaterally into the nucleus accumbens. DMI, applied repeatedly but not acutely, prevented the sedative effect of dopamine and enhanced its stimulating action, as assessed by the open-field test. Repeated administration of DMI also enhanced d-amphetamine-induced locomotor hyperactivity. The number of [3H]SCH 23390 binding sites (D-1) in the limbic system decreased while the number of [3H] spiperone ones (D-2) remained unchanged. The results indicate that, like other antidepressant drugs studied earlier, DMI enhances neurotransmission in the dopamine mesolimbic system (nucleus accumbens) of the rat.