ACTH 4-9 analogue facilitates the antiimmobility effect of antidepressants and dopamine agonists in swimming rats.

Evidence exists that the 4-10 or 4-9 fragments of adrenocorticotropic hormone (ACTH) produce some behavioral effects in animals and in humans. The present study was designed to investigate whether ACTH 4-9 interferes with the effects of antidepressants: fluoxetine (FLU), fluvoxamine (FOX), selegiline (SEL) or dopamine agonists: piribedil (PRB) or quinpirol (QPR) in forced swimming test and in open field in rats. ACTH 4-9 was given in a single dose (25, 50 or 100 micrograms/kg) or for 7 days (50 micrograms/kg/day), alone or together with antidepressants or dopamine agonists. It was shown that ACTH 4-9 alone did not influence the behavior of rats. However, when given in a single dose, ACTH 4-9 potentiated the antiimmobility effect of all antidepressants and dopamine agonists. ACTH 4-9 given for 7 days, facilitated only the effect of selegiline. The results suggest a functional interaction of ACTH 4-9 with serotonergic and dopaminergic brain mechanisms of drugs action.