Activation of Vasospasm by X-ray irradiation and hyperventilation.

在(1)低胆固醇血症和(2)饮食中含有2%胆固醇和胆酸钠引起的高胆固醇血症的情况下，通过球囊导管和x射线照射，在左冠状动脉反复剥脱内皮后，发生了晚期冠状动脉粥样硬化病变。为了阐明x射线照射在血管活性药物增强收缩中的作用，在没有内膜损伤的情况下重复x射线照射两次。冠状动脉对血管活性药物的反应在原位血管造影中被评价为管腔狭窄的变化。机械损伤左旋冠状动脉或左前降支3个月后，冠状动脉内注射5 -羟色胺或组胺使损伤部位比对侧完整部位收缩更大。剥脱5个月后，冠状动脉剥脱和x射线照射对血清素的影响比完整部位更严重。因此，我们能够降低痉挛的阈值，并增加对血清素的最大反应。静脉注射酮色林后，这种增强明显减弱。因此，5 -羟色胺-2受体功能可能被x射线照射改变。x射线照射2个月后，未剥落的病例，10马克杯/公斤剂量的血清素使完整部位和照射部位分别收缩26<正负> 3%和45<正负> 2%（部位间p<0.01）。在x线照射下，组织学上发现内膜增厚增加，即x线照射本身增强了动脉粥样硬化过程和血管对血清素的反应性。呼吸性或代谢性碱中毒时，血清素引起的x线照射部位的过度收缩从45%增加到76% （p<0.01）。因此，碱中毒激活了动脉硬化血管对致痉挛药物的反应。

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.