Activation of Vasospasm by X-ray irradiation and hyperventilation.

冠状动脉痉挛的激活在（1）低胆固醇血症和（2）高胆固醇血症（由含2%胆固醇和胆酸钠的饮食诱导）下，通过球囊导管和X射线照射反复内皮剥脱后，沿左冠状动脉产生沿着的晚期动脉粥样硬化病变。为了阐明X射线照射在血管活性剂增强收缩中的作用，在没有内膜损伤的情况下重复两次X射线照射。血管活性剂的反应进行了评价，在原位血管造影的变化，管腔narrowing.3个月后，机械损伤的内膜沿着左回旋支或左前降支冠状动脉，冠状动脉内注射5-羟色胺或组胺收缩损伤部位比对侧完整的网站。剥脱后5个月，冠状动脉段剥脱和X射线照射收缩更严重的血清素比完整的网站。因此，我们能够降低痉挛的阈值，并增加对5-羟色胺的最大反应，这种增强作用在静脉注射酮色林预处理后明显减弱。X射线照射后两个月，未裸露的病例，10 μ g/kg剂量的5-羟色胺使完整部位和照射部位分别收缩<plus-minus>26.3%和45.2%<plus-minus>（部位之间p&lt;0.01）。组织学上观察到沿着X射线照射的血管内膜增厚。也就是说，X射线照射本身增强了动脉粥样硬化过程和血管对5-羟色胺的反应性。在呼吸或代谢抑制下，在X射线照射部位，曲马多宁诱导的过度收缩从45%增加到76%（p&lt;0.01）。因此，痉挛激活了动脉血管对痉挛剂的反应性。

Activation of coronary spasm Advanced atherosclerotic lesions were produced along the left coronary artery following repeated endothelial denudation by a balloon catheter and X-ray irradiation in Gottingen miniature pigs under (1) hypocholesterolemia and (2) hypercholesterolemia induced by diet containing 2 % cholesterol and sodium cholate. To elucidate the role of X-ray irradiation in augmented constriction to vasoactive agents, X-ray irradiation was repeated twice with the absence of intimal injury. Responses of the coronary artery to vasoactive agents were evaluated in situ angiographically as changes in luminal narrowing.Three months after mechanical injury of the intima along the left circumflex or left anterior descending coronary artery, intracoronary injection of serotonin or histamine constricted more the injured site than the contralateral intact site. Five months after denudation, coronary segments denuded and X-ray irradiated constricted more severely to serotonin than the intact site. Thus, we were able to reduce the threshold for spasm and to augment the maximal responses to serotonin.Such augmentation was significantly attenuated by intravenous pretreatment with ketanserin. Accordingly, serotonin-2 receptor function may be altered by X-ray irradiation.Two months after X-ray irradiation in cases not denuded, serotonin in a dose of 10 mug/kg constricted the intact and irradiated sites by 26<plus-minus>3 % and 45<plus-minus>2 %, respectively (p<0.01 between sites). Increased intimal thickening was noted histologically along the X-ray irradiated sNamely, X-ray irradiation per se augments both the atherosclerotic process and the responsiveness of the vessel to serotonin. Under respiratory or metabolic alkalosis, serotonin-induced hyperconstriction at the X-ray irradiated site increased from 45% to 76 % (p<0.01). Thus, alkalosis activates the responsiveness of the arteriosclerotic vessel to a spasmogenic agents.