This is the first report of parallel studies of binding indices and physiological responsiveness of the "Serotonin-two" (5-HT2) receptor on the human platelet membrane. Binding indices were measured by a microassay employing [125I] ILSD as radioligand and ketanserin to define specific binding. A single receptor population was found, characterized by a KD of 1.69 ± 0.45 nM and Bmax of 14.5 ± 6.0 pmol/g protein in healty subjects. Functioning responsiveness of the platelet 5-HT2 receptor complex was assessed by measurement induced by threshold concentrations of adenosine diphosphate (ADP). A statistically significant positive correlation was found between the number of platelet 5-HT2 receptor sites (Bmax) and the magnitude of the serotonin-amplified aggregation response (r = 70, n = 38, p<0.001). Assessment 5-HT2 receptor complex should facilitate study of of the platelet 5-HT2 receptor complex should facilitate study of age, hormonal, disease, and drug effects on 5-HT2 receptor function in human subjects.
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)
- Pharmacology, Toxicology and Pharmaceutics(all)