Inhibition of platelet serotonin transport by propranolol
Rudnick, G.; Bencuya, R.; Nelson, P.J.; Zito, R.A.
Molecular Pharmacology 20(1): 118-123
1981
ISSN/ISBN: 0026-895X PMID: 7290078 Document Number: 178981
Transport of serotonin into human platelets is inhibited by the .beta.-adrenergic blocking agent, propranolol. Both D- and DL-propranolol, at a concentration of 1 .mu.M, inhibit the initial rate of serotonin transport by .apprx. 50%, but do not affect the steady-state level of accumulation. Most of the serotonin accumulated by intact platelets is stored in intracellular dense granules, this reserpine-sensitive component of platelet serotonin transport is not inhibited by propranolol. In isolated porcine platelet plasma membrane vesicles, DL-propranolol is a competitive inhibitor of serotonin transport with a KI of 1.03 .+-. 0.27 .mu.M. Propranolol displaces imipramine bound to the plasma membrane serotonin transporter. Propranolol does not inhibit transport of serotonin into membrane vesicles derived from platelet dense granules. Propranolol inhibits platelet serotonin transport at the level of the plasma membrane.