Miyachi Y
Department of Physiology, Toho University School of Medicine, Tokyo, Japan.
Experientia. 1996 Mar 15;52(3):230-3. doi: 10.1007/BF01920712.
Acute emetic response to relatively low-doses of X-irradiation on suncus (Suncus murinus) was examined. The behaviors recorded for each subject, using a video-cassette recorder system, were (1) the number of emesis, during exposure to a dose of 3.0 Gy; (2) emesis threshold. Results showed that the emetic threshold was observed at 0.85 Gy, and the number of radioemesis during exposure was 29. However, the observed threshold dose became 2.22 Gy following olfactory bulbectomy. The emetic number decreased significantly (p <0.01), and reached a value one-fourth of the sham-control. The bulbectomized suncus showed a resistance to X-irradiation. Furthermore, I examined whether the animals could also acquire radio-resistance when they were subjected to a brief of dose X-rays (0.3 Gy) prior to a exposure to 3.0 Gy. Results showed that brief pre-exposure increased the observed threshold, a pattern that was exactly the same as shown in the bulbectomized animals. Increasing the pre-exposure dose further to 0.45-0.60 Gy, however, resulted in the complete disappearance of the effect. These results suggest that only the mice pre-irradiated with 0.30 Gy acquired resistance to radiation-induced emesis.
研究了低剂量X射线对臭鼩（Suncus murinus）的急性催吐反应。使用盒式录像机系统记录每个受试者的行为，包括：（1）在接受3.0 Gy剂量照射期间的呕吐次数；（2）呕吐阈值。结果显示，呕吐阈值为0.85 Gy，照射期间的放射性呕吐次数为29次。然而，嗅球切除术后观察到的阈值剂量变为2.22 Gy。呕吐次数显著减少（p<0.01），降至假手术对照组的四分之一。嗅球切除的臭鼩对X射线照射表现出抗性。此外，我还研究了动物在接受3.0 Gy照射之前先接受一次短暂的X射线剂量（0.3 Gy）照射是否也能获得抗辐射能力。结果显示，短暂的预照射提高了观察到的阈值，这一模式与嗅球切除动物的情况完全相同。然而，将预照射剂量进一步提高到0.45 - 0.60 Gy会导致这种效应完全消失。这些结果表明，只有预先接受0.30 Gy照射的小鼠获得了对辐射诱导呕吐的抗性。
