DOPAMINE‐LIKE PROPERTIES OF EPHEDRINE IN RAT BRAIN

Abstract

Ephedrine (3.1–50 mg/kg) was given intraperitoneally to rats and was found to cause a marked increase in spontaneous locomotor activity In rats with a unilateral lesion in the substantia nigra made by stereotaxic injection of 6‐hydroxydopamine, ephedrine (12.5–150 mg/kg i.p.) caused a dose‐dependent turning towards the lesioned side Turning behaviour and increase in locomotion produced by ephedrine were antagonized by pretreatment of the animals with pimozide, amino‐oxyacetic acid or reserpine plus α‐methyl‐ρ‐tyrosine, but not by pretreatment with phenoxybenzamine, propranolol or methergoline In in vitro studies with synaptosomes prepared from rat brain, ephedrine blocked the uptake and caused the release of [3H]‐dopamine Similar results with regard to locomotion and turning behaviour were obtained with (+)‐amphetamine It is concluded that the increase in locomotion and turning behaviour produced by ephedrine is mediated through an indirect dopaminergic mechanism. 1981 British Pharmacological Society