Role of DA in the stimulant effect of DITA in mice; comparison with d-amphetamine.

The effect of DL-alpha methyltyrosine (alpha-MT), 6-hydroxydopa (6-OH DOPA), haloperidol, phenoxybenzamine and propranolol on the stimulant activity of the anorexigenic agents (3',4'-dichloro-2-(2-imidazolin-2-yl-thio)-acetophenone HBr) (DITA) and d-amphetamine was studied in male mice. The pretreatment of mice with alpha-MT, (32, 64 mg/kg i.p.), significantly reduced the increase in motor activity induced by DITA or d-amphetamine. On the other hand, pretreatment of mice with 6-OH DOPA, (100, 150 mg/kg, i.v.), did not significantly after the stimulant effect of either DITA or d-amphetamine. In the case of haloperidol, it significantly reduced the increase of motor activity induced by DITA or d-amphetamine; propranolol and phenoxybenzamine were ineffective. Our results support the hypothesis that the stimulant effect of DITA and d-amphetamine depends mainly on the integrity of the central dopaminergic rather than the noradrenergic system.