Binding of 5-hydroxytryptamine to brain hydrophobic proteins. Inhibition by structural analogues and ions

Abstract

Binding studies with hydrophobic proteins extracted from cerebral cortex homogenates by mixtures of n-butanol-water and separated by chromatography on LH-20 Sephadex, have been done.5-HT-(14C) binds to this fraction with high affinity.This binding saturates with 5 X 10(-06) M 5-HT, with K1/2 value of 1 X 10(-7) M.Binding is partially inhibited by a mixture of alkaloids ergocornine, ergocrystine and ergocryptine, as well as by tryptamine.A light inhibition has been observed in presence of tryptophan or lysine, but none in presence of methysergide or hypoxanthine.Binding is strongly inhibited by monovalent ions (Li+, Na+ and NH4+).The influence of pH in the incubation medium has also been studied; maximal rates of binding were obtained at neutral pH.