Calcium-induced calcium release activates contraction in intact cardiac cells.
The "caged" calcium chelator Nitr-5 was incorporated into isolated rat ventricular myocytes. Brief illumination with ultra-violet light made the cell twitch. The light-induced twitch was inhibited by ryanodine (1-10/microM) suggesting that it resulted from calcium-induced release of calcium from the sarcoplasmic reticulum. Inhibition of the Ca current (Ni, 10 mM) abolished the electrically stimulated twitch but did not inhibit the light-induced twitch. These results provide direct evidence for the importance of Ca-induced Ca release in excitation-contraction coupling in the heart.
Valdeolmillos
M
M
Department of Physiology, University College London, Great Britain.
O'Neill
S C
SC
Smith
G L
GL
Eisner
D A
DA
D000818:Animals; D002118:Calcium / Q000493:pharmacokinetics*; D002478:Cells, Cultured; D009200:Myocardial Contraction; D009206:Myocardium / Q000378:metabolism*; D051381:Rats; D012433:Ryanodine / Q000378:metabolism
D012433:Ryanodine; D002118:Calcium