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 cardioprotectiv e effects of the extract from radix stephaniae tetrandrae (RST) and its ind ividual compounds, tetrandrine (Tet) and fanchinoline (Fan). Secondly, we a lso compared the cardiac effects of the individual compounds and the RST ex tract with those of verapamil, a classical Ca2+ channel blocker. The Langen dorff isolated perfused rat heart preparation was used. Regional ischaemia and reperfusion was employed to induce myocardial infarct and arrhythmia. I nfarct, arrhythmia, heart rate and coronary artery how were determined in h earts treated with vehicle, RST extract, Tet, I;an, or verapamil. It was fo und that RST extract, of which only 9% was Tet, and Tet alone produced equa lly potent ameliorating effects on arrhythmia and infarct induced by ischae mia and reperfusion without further inhibiting ischaemia-reduced heart rate and coronary artery how. Fan had no effects on arrhythmia and infarct indu ced by ischaemia and reperfusion; but it induced S-T segment elevation and further reduced heart rate and coronary artery flow during ischaemia. Verap amil also ameliorated the effects of ischaemia and reperfusion on arrhythmi a and infarct, It should be noted that 1 muM verapamil, that produced compa rable effects on infarct and arrhythmia to the RST extract and Tet, further inhibited heart rate during ischaemia, The results indicate that the RST e xtract produces equally potent cardioprotective and anti-arrhythmic effects as Tet alone. Both RST extract and Tet may be better choices for the treat ment of arrhythmia and infarct induced by myocardial ischaemia and reperfus ion than the classical Ca2+ channel blocker, verapamil as they do not furth er reduce heart rate during ischaemia, (C) 2001 Elsevier Science Inc. All r ights reserved.