@article{APS4545,
author = {Man-wen Jin and Da-chao Fang and Ming-xing Jiang},
title = {Influence of tetrandrine on positive inotropic action of isoproterenol and CaCl2 and on excitation-contraction coupling in isolated cat papillary muscles},
journal = {Acta Pharmacologica Sinica},
volume = {3},
number = {2},
year = {2016},
keywords = {},
abstract = {The effects of tetrandrine, verapamil, propranolol and practolol on isoproterenol dose-response relationships and the influence of tetrandrine, verapamil and nifedipine on calcium dose-response relationships and on excitation-contraction coupling were investigated on isolated cat papillary muscles.
Propranolol and practolol competitively antagonized isoproterenol. Tetrandrine and verapamil also antagonized isoproterenol but in a non-competitive manner.
Tetrandrine，verapamil and nifedipine shifted calcium dose-response curves to the right, and acted as non-competitive antagonists of calcium, as a plot of log (x-1) vs -log [B] resulted in straight lines with slopes of -0.43, -0.55 and -0.42, respectively.
Tetrandrine, verapamil and nifedipine resulted in excitation-contraction uncoupling. It was suggested that tetrandrine inhibited the inward diplacement of calcium through the voltage-dependent channel.
The results support our speculation that tetrandrine is a calcium antagonist of plant origin.},
issn = {1745-7254}, url = {http://www.chinaphar.com/article/view/4545}
}