Flow- and bradykinin-induced nitric oxide production by endothelial cells is independent of membrane potential.
The objective of this study was to evaluate the role transmembrane potential plays in flow-induced nitric oxide (NO) production in endothelial cells (EC). NO production was monitored by measuring intracellular guanosine 3',5'-cyclic monophosphate (cGMP) and extracellular nitrite plus nitrate (NOx). Primary human umbilical vein endothelial cells (HUVEC) were exposed to laminar flow (22 dyn/cm2) of medium with 5.4 mM KCl (control medium) with or without 3 mM tetraethylammonium chloride (TEA) or 90 mM KCl (K(+)-rich medium). Bradykinin (BK) was added to time-matched stationary cultures to give a final concentration of 5 nM. With control medium, 30 s, 2 min, and 3 h of treatment with flow or 2 min of treatment with BK resulted in an approximately threefold increase in cGMP over stationary cultures. Depolarization with KCl or TEA did not influence cGMP production in flow-treated or stationary cultures. Flow of either control or potassium-rich medium resulted in an approximately 10-fold increase in average NOx production rate over 3 h compared with stationary cultures. Taken together these data indicate that neither membrane hyperpolarization nor normal membrane potential is necessary for flow- or BK-induced NO production by HUVEC.
Gooch
K J
KJ
Department of Chemical Engineering, Pennsylvania State University, University Park 16802, USA.
Frangos
J A
JA
D001775:Blood Circulation; D001920:Bradykinin / Q000494:pharmacology*; D002478:Cells, Cultured; D006152:Cyclic GMP / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects* / Q000502:physiology*; D006801:Humans; D008564:Membrane Potentials; D009569:Nitric Oxide / Q000096:biosynthesis*; D013997:Time Factors
D009569:Nitric Oxide; D006152:Cyclic GMP; D001920:Bradykinin