Effect of phenmetrazine, aminorex and ( ) p-chloramphetamine on the motor activity and turnover rate of brain catecholamines.

1. The minimal doses (mumol/kg i.v.) of phenmetrazine, (+/-)-p-chloramphetamine, and aminorex which increase motor activity are 5.6, 3.5, and 1.5, respectively. We detected stereotype behaviour neither in rats receiving intravenous doses 3 times greater nor in animals injected intraperitoneally with 44, 62 and 112 mumol/kg of (+/-)-p-chloramphetamine, aminorex and phenmatrazine, respectively.2. The latter doses of the three amphetamine congeners were tested for their action on tissue monoamine content. Only (+/-)-p-chloramphetamine decreased the concentration of tel-diencephalon 5-hydroxytryptamine (5-HT) and this decrease lasted longer than 24 hours. This and the other two amphetamine congeners failed to affect the concentration of noradrenaline (NA) in brain, heart and lung.3. Aminorex (1.5 mumol/kg i.v.) and (+/-)-p-chloramphetamine (3.5 mumol/kg i.v.) decreased the turnover time of striatum dopamine (DM) but failed to change the turnover time of tel-diencephalon and brainstem NA. Phenmetrazine (5.6 mumol/kg i.v.) changed neither the turnover time of striatum DM nor that of NA in the two brain areas assayed.