THE INFLUENCE OF GANGLIOSIDES ON SEROTONIN BINDING AND UPTAKE BY HUMAN PLATELETS

It has been shown that gangliosides exert an influence on serotonin (5 -HT) binding and uptake by human platelets. The effect depends on gang lioside structure. In particular, GT1b increases the number of 5-HT bi nding sites by 40 to 60%, and GM1, GM3 and GD3 decrease it by 20 to 40 %. None of the gangliosides tested influences the affinity of the 5-HT binding sites with K-D = 60 +/- 10 nM. It has been found that loading platelets with GT1b increases the rate of 5-HT uptake and increases t he capacity of platelets for this monoamine. It is concluded that gang liosides incorporated into platelet membranes influence the number of 5-HT binding sites on the serotonin transporter.