Radiation and G tolerance in rats

Male hooded rats were exposed to 2100 rad 60Co radiation and 18 h later were exposed to +Gz acceleration until heart rate was reduced to 50% of baseline rate. G tolerance was 9.2% less in irradiated rats than in controls. Although small, this difference was significant at p less than 0.05. A similar group of rats was anesthetized 18 h postirradiation and carotid mean arterial pressures were measured. Mean arterial pressure was 122.1 torr for controls and 114.5 for irradiated. This difference was not significant.