Endothelium-dependent effect of bradykinin and ATP on rabbit ventricular myocytes.
We have investigated the effects of bradykinin (BK) and ATP on Ca2+ transient induced by electrical-field stimulation in freshly isolated rabbit ventricular myocytes, in the presence or absence of rabbit aortic endothelial cells. BK and ATP induced an increase in intracellular Ca2+ concentration ([Ca2+]i) in the endothelial cells, but had no significant effect on Ca2+ transient in electrical-field stimulated ventricular myocytes. In the presence of cultured endothelial cells, the amplitude of Ca2+ transient induced by electrical stimulation in ventricular myocytes was decreased. BK and ATP further reduced the amplitude of Ca2+ transient induced by electrical stimulation in ventricular myocytes. These data show that BK and ATP have endothelium-dependent depressing effects on ventricular myocytes and indicate that substances released from endothelial cells in response to BK and ATP stimulation can modulate ventricular myocytes excitation-contraction coupling. However, identification of the cardioactive mediators produced by the endothelial cells requires further study.
Ou
Y J
YJ
Department of Physiology and Institute of Cardiovascular Sciences & Medicine, The University of Hong Kong, SAR of China.
Shan
Q X
QX
Bourreau
J P
JP
D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D001920:Bradykinin / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D004558:Electric Stimulation; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D006352:Heart Ventricles / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D066298:In Vitro Techniques; D017136:Ion Transport / Q000187:drug effects; D009200:Myocardial Contraction / Q000187:drug effects; D009206:Myocardium / Q000166:cytology / Q000378:metabolism*; D011817:Rabbits
D000255:Adenosine Triphosphate; D001920:Bradykinin; D002118:Calcium