Effects of tetrandrine on cardiovascular electrophysiologic properties.
Abstract
Tetrandrine (Tet) is one of the best characterized Ca2+ channel blocker of plant
origin. It can affect cardiovascular electrophysiologic properties in following
field: inhibit the contractility, +/-dt/dpmax, and automaticity of myocardium,
prolong the FRP, and exert concentration-dependent negative inotropic and
chronotropic effects without altering cardiac excitability. Tet directly blocks
both T-type and L-type calcium current in ventricular cells and vascular smooth
muscle cells, but it does not shift the I-V relationship curve of ICa. All its
effects would be beneficial in the treatment of angina, arrhythmias, and other
cardiovascular disorders. Tet also directly inhibits the activity of BKCa channel
in endothelial cell line and also inhibits Ca2+-release-activated channels in
vessel endothelial cells, which might significantly contribute to the change of
endothelial cell activity.
Keywords:
origin. It can affect cardiovascular electrophysiologic properties in following
field: inhibit the contractility, +/-dt/dpmax, and automaticity of myocardium,
prolong the FRP, and exert concentration-dependent negative inotropic and
chronotropic effects without altering cardiac excitability. Tet directly blocks
both T-type and L-type calcium current in ventricular cells and vascular smooth
muscle cells, but it does not shift the I-V relationship curve of ICa. All its
effects would be beneficial in the treatment of angina, arrhythmias, and other
cardiovascular disorders. Tet also directly inhibits the activity of BKCa channel
in endothelial cell line and also inhibits Ca2+-release-activated channels in
vessel endothelial cells, which might significantly contribute to the change of
endothelial cell activity.