The hypothesis that the action of hallucinogenic drugs is mediated by a depression of the activity of brain serotonergic (raphe) neurons was tested by examining the behavioral effects of d -lysergic acid diethylamide (LSD) while studying the activity of raphe neurons in freely moving cats. Although the results provide general support for the hypothesis, there were several important...
The roles of catecholamine and 5‐hydroxytryptamine (5‐HT) release in mediating backward walking and circling were studied in rats. These behaviours occurred in animals given 15mg/kg intraperitoneally of (+)‐amphetamine (which predominantly releases catecholamines) or either p ‐chloroamphetamine or fenfluramine (which predominantly release 5‐HT). They also occurred when smaller doses of...
In blood platelets of rabbits isolated by a stractan gradient and incubated in a protein‐poor medium, tryptamine, 5‐hydroxytryptamine (5‐HT) and derivatives, quipazine and mescaline caused a shape change. This shape change was inhibited by low concentrations of methysergide. The most potent antagonists of the 5‐HT‐induced shape change included ergoline derivatives and neuroleptic drugs, which...
To test the possible involvement of serotonin-containing cells of the midbrain in mediating the effects of mescaline on startle responding, electrolytic lesions were made in either the dorsal or median raphe nucleus in rats. Decreases in either striatal or hippocampal tryptophan hydroxylase activity confirmed the effectiveness of the lesions. One week later, startle was measured in response to...
A simplified method of studying the surfacing reaction of goldfish to hallucinogens is described. Goldfish weighing up to three grams are injected intracranially. Employing this method, d-lysergic acid diethylamide (LSD-25), d-2-acetyl lysergic acid diethylamide (ALD-52), 1-methyl d-lysergic acid butano-lamide (UML-491), and 5-methoxy dimethyl tryptamine (5-MEO-DMT) were found to be as...
Rats were tested for shock elicited fighting under various doses of N,N-dimethyltryptamine (0.12, 0.25, 0.50, 1.0, 4.0, 8.0 mg/kg) and 5-methoxy-N,N-dimethyltryptamine (0.06, 0.12, 0.5, 2.0 mg/kg). Both drugs produced an inhibition of fighting at higher doses but no significant effects at lower doses. The effects of these drugs on shock elicited fighting, as well as on other behaviors, thus...
J D Sinden, D M Atrens; 5-Methoxy-NN-dimethyltryptamine: differential modulation of the rewarding and aversive components of lateral hypothalamic self-stimulati
D-Lysergic acid diethylamide and D-2-bromolysergic acid diethylamide are competitive antagonists of the histamine activation of adenylate cyclase [ATP pyrophosphate-lyase (cyclizing); E.C. 4.6.1.1] in broken cell preparations of the hippocampus and cortex of guinea pig brain. The adenylate cyclase is linked to the histamine H2-receptor. Both D-lysergic acid diethylamide and D-2-bromolysergic...
Two experiments were carried out using a fixed ratio (FR) schedule of water reinforcement to determine the efficacy of two serotonin (5HT) depleting agents (p-chloroamphetamine, 5, 7-dihydroxytryptamine) in altering sensitivity to a low dose of LSD (0.02 MG/KG). The results showed that while both p-chloroamphetamine (PCA) and 5, 7 dihydroxytryptamine (5, 7 DHT) were efficacious in reducing...
Lysergic acid diethylamide (LSD), 0.05 mg/kg and 0.20 mg/kg, significantly decreased plasma prolactin (PRL) levels in male rats. LSD, 0.20 mg/kg, also inhibits the increase in plasma PRL levels produced by chlorpromazine (CPZ), 5 mg/kg, and alpha-methylparatyrosine (AMPT), 50 mg/kg, both of which interfere with dopaminergic inhibition of PRL secretion. LSD was more potent than methysergide, a...