High-affinity 3H-serotonin binding to caudate: inhibition by hallucinogens and serotoninergic drugs.
Psychopharmacology – September 15, 1978
Source: PubMed
Summary
Specific binding of 3H-serotonin to calf caudate homogenate reveals a dissociation constant of 2nM and 14 femtomoles of specific sites per milligram of protein. Notably, serotonin agonists and antagonists predominantly inhibit this binding. For instance, bufotenin inhibits at 6nM, while LSD requires 9.5nM for a similar effect. Other notable concentrations include 12nM for 5-methoxytryptamine and 16nM for methysergide. These findings highlight the potency of various serotonergic compounds in modulating serotonin binding, with implications for understanding neurotransmitter interactions.
Abstract
The specific binding of 3H-serotonin to calf caudate homogenate was studied. The dissociation constant was 2nM and the number of specific sites was 14fmoles/mg protein. Of many drugs tested, inhibition of specific 3H-serotonin binding occurred almost exclusively with serotonin agonists and antagonists. The concentrations for 50% inhibition of 3H-serotonin binding by serotonergic agonists follow: bufotenin, 6nM; 5-methoxytryptamine, 12 nM; psilocin, 35nM; dimethyltryptamine, 220 nM; and tryptamine, 270 nM. The concentrations for the antagonists were: LSD 9.5 nM; methysergide 16nM and metergoline 25nM.