Premium
Verapamil inhibits serotonin uptake of endothelial cells in culture by a mechanism unrelated to Ca 2+ channel blockade
Author(s) -
Lee S.L.,
Long K.,
Ueda S.,
Fanburg B. L.
Publication year - 1987
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1041320126
Subject(s) - verapamil , stimulation , serotonin , chemistry , blockade , pharmacology , endocrinology , medicine , mechanism of action , calcium , biology , biochemistry , in vitro , receptor
Verapamil inhibited Na + ‐dependent uptake of serotonin (5‐HT) by bovine pulmonary artery endothelial cells in culture both exposed to room air and stimulated by prior exposure to anoxia. The effect of verapamil occurred even in the absence of Ca 2+ from the assay medium. Although absence of Ca 2+ from the medium moderately reduced 5‐HT uptake, stimulation of uptake was nevertheless observed for cells previously exposed to anoxia. Verapamil altered the Km, but not the Vmax, of 5‐HT uptake. There was no change in 45 Ca 2+ uptake or release by cells previously exposed to anoxia as compared to those exposed to room air and verapamil did not influence 45 Ca 2+ fluxes by either set of cells. It is concluded that verapamil inhibits 5‐HT uptake by endothelial cells through a mechanism other than Ca 2+ channel blockade; the results are consistent with competitive inhibition of a 5‐HT carrier. The stimulatory effect of anoxia on 5‐HT uptake does not occur through a change in Ca 2+ fluxes.