INHIBITING EFFECTS OF SEROTONIN ANTAGONISTS ON THE PROLIFERATION OF MERCURIC-CHLORIDE STIMULATED HUMAN PERIPHERAL-BLOOD LYMPHOCYTES-T

The serotonin antagonists ketanserin and methiotepine were tested for a modulating effect on the proliferative response of human peripheral blood T lymphocytes to mercuric chloride. This response was inhibited by ketanserin at 8 X 10(-5) mol/l and by methiotepine at 8.0 x 10(-6) mol/l. There were no additive effects at these concentrations of antagonists and at 10(-5) mol/l of serotonin. Low concentrations of ketanserin eliminated the inhibiting effect of serotonin on mercuric chloride induced proliferation of T lymphocytes. It thus seems as if the inhibiting effect of serotonin on T lymphocytes is mediated by 5-HT1c, or 5-HT2 receptors, while the mechanism for the intrinsic inhibiting effect of the antagonists at present is unknown.