Borison H L, McCarthy L E, Douple E B, Johnson J, Borison R
Radiat Res. 1987 Mar;109(3):430-9.
A dose-response relationship was established in normal unanesthetized cats for emetic incidence, latency to onset of vomiting, and duration of emetic activity over a period of 24 h after whole-body exposure to 60Co radiation at selected doses between 7.5 and 90 Gy. Each episode of vomiting, i.e., retching and expulsion, was recorded oscillographically as its characteristic intrathoracic pressure waveform by means of a catheter inserted some days before into the superior vena cava. The gamma-radiation dose of 45 Gy evoked vomiting optimally with an incidence of 92% and an average onset time of 98 min. When administered to animals prepared chronically with surgical ablation of the area postrema, the same dose of radiation evoked vomiting in four of five test cases and with an average time to onset that was not by either measure significantly different from normal. Vomiting was also elicited in all of six normal cats exposed to an intestinal dose of 45 Gy X radiation with the head shielded. The same form of irradiation evoked vomiting in two of three chronically postremectomized cats. Successful ablation of the area postrema was determined functionally by emetic refractoriness to an injection of digitalis and confirmed for completeness by histological examination. It is concluded that the area postrema is not an essential element in the reflex mechanism of radiation-induced vomiting and, therefore, no physiological basis exists for dependence on a centrally acting chemogenic factor in radioemesis.
在正常未麻醉的猫身上建立了剂量反应关系，涉及催吐发生率、呕吐发作潜伏期以及在全身暴露于7.5至90 Gy选定剂量的60Co辐射后24小时内催吐活动的持续时间。每次呕吐发作，即干呕和呕吐，通过几天前插入上腔静脉的导管，以其特征性的胸内压力波形进行示波器记录。45 Gy的γ辐射剂量诱发呕吐的效果最佳，发生率为92%，平均发作时间为98分钟。当给予经手术切除最后区的慢性制备动物时，相同剂量的辐射在五个测试案例中的四个中诱发了呕吐，且平均发作时间在两种测量方法上与正常情况均无显著差异。在六只头部屏蔽、接受45 Gy X射线肠道剂量照射的正常猫中，也都引发了呕吐。同样形式的照射在三只慢性切除最后区的猫中的两只中诱发了呕吐。最后区的成功切除通过对洋地黄注射的催吐不应性进行功能测定，并通过组织学检查确认其完整性。结论是，最后区不是辐射诱发呕吐反射机制中的必要元素，因此，在放射性呕吐中依赖中枢作用的化学成因因子不存在生理基础。
