SEROTONIN AND SEROTONINERGIC AGENTS AFFECT PROLIFERATION OF NORMAL AND TRANSFORMED LYMPHOID-CELLS

Blastogenic transformation of murine spleen cells elicited with concan avalin A was suppressed by serotonin 10(-12) to 10(-6) M, and marginal ly stimulated by its antagonists ketanserin and propranolol in low con centrations (10(-15) to 10(-11) M). Ketanserin (5-HT2 receptor ligand) and propranolol (5-HT1A and beta-adrenergic ligand) did not block the suppressive effect of serotonin if used along with it in aquimolar co ncentrations (10(-9) M). Ergot-alkaloid dihydroergosine suppressed, wh ereas dihydroergotoxin stimulated the blastogenic transformation. Oppo site effects of the agents were obtained in experiments with mouse mye loma X63/Ag 8.653 and hybridoma SHV 125 cell lines, which unlike norma l lymphoid cells, are homologous cell populations and proliferate spon taneously. The data indicate that serotonin and its antagonists interf ere directly with mitosis and/or autocrine stimulation of target cells .