Effect of excitability-inducing material on regenerative Ca++ release of rat ventricular muscle.
The effects of excitability-inducing materials (EIM) and electrical stimulation on Ca+(+)-induced Ca++ release were studied in this experiment. Direct application of three EIM (bacterial EIM, alamethicin, Nal) did not release Ca++ from skinned rat cardiac fibers or from an SR suspension. Direct electrical stimulation of the SR suspension had no effect on Ca++ release either. However, both electrical stimulation and pre-treatment with an EIM augmented Ca+(+)-induced Ca++ release in the skinned fiber and led to increased contractility of the fiber in a dose-dependent manner. When electrical stimulation and EIM application were superimposed, their effects were additive, suggesting that information transfer across the junction between T-tubule and SR is at least chemical in nature.
Kang
D H
DH
Department of Physiology, Yonsei University College of Medicine, Seoul, Korea.
Lee
Y H
YH
Song
H J
HJ
D000408:Alamethicin / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D004558:Electric Stimulation; D006352:Heart Ventricles / Q000378:metabolism*; D051381:Rats; D012519:Sarcoplasmic Reticulum / Q000378:metabolism*; D012974:Sodium Iodide / Q000494:pharmacology; D016276:Ventricular Function
D000408:Alamethicin; D012974:Sodium Iodide; D002118:Calcium