Chloride and cation currents activated by bradykinin in coronary venular endothelial cells.
Bradykinin (BK) is known to activate several types of ion channels in endothelial cells, including a K+ channel and a nonselective cation channel. The predominant BK-activated current in most endothelial cells appears to be an outward, Ca(2+)-activated K+ current. We consistently recorded a rapidly activated, spontaneously inactivated inward current stimulated by BK in bovine coronary venular endothelial cells (CVECs). With the use of a whole cell, perforated patch recording mode, the average magnitude of the current was -293 +/- 38 pA. Simultaneous measurements of current and intracellular Ca2+ concentration ([Ca2+]i) showed that the inward current correlated closely with transient increases in [Ca2+]i due to Ca2+ release from intracellular stores. The current could be blocked by 4,4'-diisothiocyanatostilbene-2, 2'-disulfonic acid (DIDS) but not by La3+, and it persisted in Ca(2+)-free/Na(+)-free solution. When intra- and/or extracellular Cl- concentrations were altered, the reversal potential of the current shifted according to the calculated Cl- -equilibrium potential, indicating that the current was carried primarily by Cl-. Another inward current was also activated by BK. This current was slower to activate, could be blocked by La3+, but was not blocked by DIDS. The time course of the slowly activated current correlated with the plateau phase of the BK-stimulated [Ca2+]i increase, which was similar to the behavior of a nonselective cation current reported previously. We propose that these two currents may contribute to the depolarizations and net inward currents induced by BK in this cell line.
Song
J
J
Department of Medical Physiology, Texas A & M University Health Science Center, College Station 77843-1114.
Davis
M J
MJ
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000494:pharmacology; D000818:Animals; D001011:Aorta; D001920:Bradykinin / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology; D002417:Cattle; D018118:Chloride Channels / Q000187:drug effects / Q000502:physiology*; D002712:Chlorides / Q000494:pharmacology; D003331:Coronary Vessels / Q000502:physiology*; D004553:Electric Conductivity; D004730:Endothelium, Vascular / Q000502:physiology*; D007473:Ion Channels / Q000502:physiology*; D007700:Kinetics; D007811:Lanthanum / Q000494:pharmacology; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology; D012964:Sodium / Q000494:pharmacology; D014699:Venules / Q000502:physiology
D018118:Chloride Channels; D002712:Chlorides; D007473:Ion Channels; D015221:Potassium Channels; D007811:Lanthanum; D012964:Sodium; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D001920:Bradykinin; D002118:Calcium