Effects of certain drugs and enzymes on the electrophoretic mobility of rabbit blood platelets.

Abstract

Electrophoretic mobility of rabbit blood platelets was measured by cell electrophoresis and by this method electrochemical properties of platelets and 5-hydroxytryptamine (5HT)-platelets or various 5HT releasers-platelets interactions were examined. It was found that the mobility of platelets was —0.98 μ /sec/volt/cm in 0.02 M Tris saline (pH 7.5). Decreases in the mobility of platelets by treatment with neuraminidase or trypsin were observed at 40% and 20% respectively and sialic acid was released by both treatments. The pattern of cation charge-reversal spectra of platelets was similar to the carboxyl and phosphate groups in spectra of Bungenberg de Jong. Addition of 5HT, lipopolysaccharide (LPS) and heparin did not influence the mobility of platelets in the neutral pH region. Under the conditions producing release of 5HT from platelets, the treatments with the plasma 5HT releasing factor, thrombin, LPS or chlorpromazine decreased the mobility of platelets, while that with reserpine, tyramine or imipramine did not. These findings suggest that carboxyl group of sialic acid is responsible for the negative charge of platelets surface but it may not interact with 5HT and that the membrane is one of the sites of 5HT releasing actions of the plasma factor, thrombin, LPS or chlorpromazine.