Structural Requirements for Uptake into Serotoninergic Neurones

Abstract

Whether non-hydroxylated tryptamines and 4-chloroamphetamine use the membrane 5-hydroxytryptamine [5-HT] carrier to pass into serotoninergic neurons was studied. The accumulation and deamination of 14C-tryptamine by mouse brain slices or homogenates of rat hypothalamus were not inhibited by cocaine or norzimelidine, a selective inhibitor of the neuronal 5-HT uptake. The prevention by .alpha.-methyltryptamine (10 mg/kg, i.p.), .alpha.-ethyltryptamine (20 mg/kg i.p.) and 4-chloroamphetamine (20 mg/kg i.p.) of the irreversible inhibition of monoamine oxidase by pheniprazine (2.5 mg/kg i.p.) and clorgyline (5 mg/kg i.p.) in serotoninergic synaptosomes from mouse brain was not antagonized by pretreatment with norzimelidine (20 mg/kg i.p.). The partial preventing effect of .alpha.-ethyl-4-methyl-m-tyramine (H 75/12, 2 .times. 50 mg/kg i.p.) was antagonized by norzimelidine. Non-hydroxylated tryptamines and 4-chloroamphetamine are apparently not transported by the 5-HT carrier.