The Effect of X‐irradiation on the Response of the Intestine to Acetylcholine and on Its Content of “Pseudo”‐cholinesterase

Recently an investigation was published of the effect of x-irradiation on the pressor amines in the adrenal medulla (Anderson, Blaschko, Burn, and Mole, 1951).In the course of this work the effect of x-irradiation in causing changes in the intes- tine was noted.The rats suffered from diarrhoea, which indicated increased motility of the intestines, while, on the other hand, when the rats were killed at the end of 72 hr., the lower bowel appeared to be distended and flaccid.We decided to investigate the response of isolated loops of intestine taken from rats after irradiation in order to see if there was any change in their contractile response to acetylcholine and to histamine.We now describe this work in which we found that isolated loops of intestine show changes in response to the stimulant action of acetylcholine after irradiation, but not in response to histamine.Since the effects observed might be due to a change in the amount of cholinesterase, we made determinations of the amounts of this enzyme, and found changes in this also.