Evidence for a central 5‐hydroxytryptamine receptor stimulation by lysergic acid diethylamide

Abstract

1 Lysergic acid diethylamide (LSD) and the 5-hydroxytryptamine (5-HT) precursor, 5-hydroxytryptophan produced similar functional effects in rat spinal cord and brain to the 5-hydroxytryptamine precursor 5-hydroxytryptophan, which indicates that LSD stimulates central 5-HT receptors. 2 By means of combined histochemical and biochemical techniques it was found that LSD reduced the turnover rate of brain and spinal cord 5-HT, studied after inhibition of the tryptophan hydroxylase by α-propyldopacet-amide. The turnover of brain noradrenaline but not dopamine was somewhat accelerated. 3 The functional and chemical effects by LSD were related to dose and to time. They were not observed after the LSD analogues 2-bromo-LSD and methysergide. 4 The retardation of the 5-HT turnover by LSD may be due to negative feed-back mechanisms evoked by direct stimulation of the central 5-HT receptors.