[Effect of xanthnotoxol on contraction of rabbit thoracic aortic strips].

To study the effect of xanthnotoxol (XT) on contractility of rabbit thoracic aorta strips and its relationship with Ca2+.Routine experimental methods for isolated thoracic aorta strips were adopted.XT and verapamil (Ver) can make the dose-response curve of rabbit thoracic aorta strips induced by NE, KCl, CaCl2 shifed right (the pD'2 of KCl and CaCl2 value was 3.58 +/- 0.07 and 4.12 +/- 0.12) and depressed the maximal responses. Like verapamil (Ver), it is accomplished by calcium antagonism. XT could selectively block the voltage dependence calcium channel (VDC), and have no effect on the receptor operated calcium channel (ROC).It suggested XT had selectly blocking effect on voltage dependence calcium channel.