Different effects of zimelidine on the reinforcing properties of d-amphetamine and morphine on conditioned place preference in rats.

The possibility that serotoninergic mechanisms control the reinforcing properties of d-amphetamine and morphine was investigated in rats, using zimelidine, a potent and selective serotonin uptake blocker and the conditioned place preference test design. Zimelidine dihydrochloride 20 mg/kg did not cause place aversion and did not modify the place preference induced by 5 mg/kg morphine hydrochloride. Place preference induced by 5 mg/kg d-amphetamine sulphate was completely blocked by pretreatment with zimelidine. The results suggest that the reinforcing properties of d-amphetamine, but not of opioid agonists, may be reduced by agents which increase serotonin transmission in the brain.