Cardiac effects of the extract and active components of radix stephaniae tetrandrae. II. Myocardial infarct, arrhythmias, coronary arterial flow and heart rate in the isolated perfused rat heart.
The primary purpose of the present study was to compare the cardioprotective effects of the extract from radix stephaniae tetrandrae (RST) and its individual compounds, tetrandrine (Tet) and fanchinoline (Fan). Secondly, we also compared the cardiac effects of the individual compounds and the RST extract with those of verapamil, a classical Ca2+ channel blocker. The Langendorff isolated perfused rat heart preparation was used. Regional ischaemia and reperfusion was employed to induce myocardial infarct and arrhythmia. Infarct, arrhythmia, heart rate and coronary artery flow were determined in hearts treated with vehicle, RST extract, Tet, Fan, or verapamil. It was found that RST extract, of which only 9% was Tet, and Tet alone produced equally potent ameliorating effects on arrhythmia and infarct induced by ischaemia and reperfusion without further inhibiting ischaemia-reduced heart rate and coronary artery flow. Fan had no effects on arrhythmia and infarct induced by ischaemia and reperfusion; but it induced S-T segment elevation and further reduced heart rate and coronary artery flow during ischaemia. Verapamil also ameliorated the effects of ischaemia and reperfusion on arrhythmia and infarct. It should be noted that 1 microM verapamil, that produced comparable effects on infarct and arrhythmia to the RST extract and Tet, further inhibited heart rate during ischaemia. The results indicate that the RST extract produces equally potent cardioprotective and anti-arrhythmic effects as Tet alone. Both RST extract and Tet may be better choices for the treatment of arrhythmia and infarct induced by myocardial ischaemia and reperfusion than the classical Ca2+ channel blocker, verapamil as they do not further reduce heart rate during ischaemia.
Yu
X C
XC
Department of Physiology, Faculty of Medicine, The University of Hong Kong, Hong Kong.
Wu
S
S
Wang
G Y
GY
Shan
J
J
Wong
T M
TM
Chen
C F
CF
Pang
K T
KT
D000470:Alkaloids / Q000627:therapeutic use*; D000818:Animals; D001145:Arrhythmias, Cardiac / Q000517:prevention & control; D044182:Benzylisoquinolines; D002121:Calcium Channel Blockers / Q000627:therapeutic use*; D003326:Coronary Circulation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004365:Drugs, Chinese Herbal / Q000627:therapeutic use*; D006321:Heart / Q000187:drug effects / Q000503:physiopathology; D006339:Heart Rate / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D009203:Myocardial Infarction / Q000503:physiopathology / Q000517:prevention & control*; D015428:Myocardial Reperfusion Injury / Q000503:physiopathology / Q000517:prevention & control*; D010477:Perfusion; D051381:Rats; D017207:Rats, Sprague-Dawley; D014700:Verapamil / Q000627:therapeutic use
D000470:Alkaloids; D044182:Benzylisoquinolines; D002121:Calcium Channel Blockers; D004365:Drugs, Chinese Herbal; C009438:tetrandrine; C060802:fangchinoline; D014700:Verapamil