ABSTRACT
The effects of d,1-alpha-methyltyrosine (alphaMT), haloperidol, phenoxybenazmine, propranolol, methysergide and cyproheptadine on the anorexigenic activities of DITA and d-amphetamine were studied in male mice. The pretreatment of mice with methysergide (10 mg/kg, s.c.), cyproheptadine (5 mg/kg, i.p.), phenoxybenzamine (10 mg/kg, i.p.), and propranolol (5 mg/kg, i.p.) failed to alter the anorexigenic effect of DITA and d-amphetamine. On the other hand, alphaMT (32 mg/kg, i.p.) and haloperidol (0.5 mg/kg, i.p.) significantly antagonized the anorexigenic effect of DITA and d-amphetamine. Our data indicate that the anorexigenic activities of DITA and d-amphetamine are mediated mainly through the dopaminergic system.
Subject(s)
Acetophenones/pharmacology , Appetite Depressants/pharmacology , Dextroamphetamine/pharmacology , Dopamine/metabolism , Eating/drug effects , Imidazoles/pharmacology , Acetophenones/antagonists & inhibitors , Animals , Appetite Depressants/antagonists & inhibitors , Cyproheptadine/pharmacology , Dextroamphetamine/antagonists & inhibitors , Haloperidol/pharmacology , Imidazoles/antagonists & inhibitors , Male , Methyltyrosines/pharmacology , Methysergide/pharmacology , Mice , Phenoxybenzamine/pharmacology , Propranolol/pharmacologyABSTRACT
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.
Subject(s)
Acetophenones/pharmacology , Dextroamphetamine/pharmacology , Imidazoles/pharmacology , Animals , Haloperidol/pharmacology , Hydroxydopamines/pharmacology , Male , Methyltyrosines/pharmacology , Mice , Motor Activity/drug effects , Phenoxybenzamine/pharmacology , Propranolol/pharmacology , Time FactorsABSTRACT
Rats given diets containing jack bean had superior performance during learning and testing of level pressing compared with rats given control diets. To evaluate the factors which might have contributed to the differences in their performance, the testing conditions, testing schedules, and the reinforcement were varied. The results strongly suggested that the rate of learning depended largely on factors inherent within the individual animals. The rats preferred the reinforcement, Noyes pellets, to diets containing jack bean. Therefore the superior performance of rats given diets containing jack bean could be, to a certain extent, due to their motivation to lever press for Noyes pellets. However, there was also evidence suggesting that other factors in jack bean enhanced the behavioral performance of rats when water droplets were used as the reinforcement.
