Reactions of the urinary bladder in canine anaphylaxis.

Abstract

As an index to possible smooth muscle reactions, we have studied the pressure changes in the urinary bladder during canine anaphylactic shock, with parallel tracings of the changes in the arterial blood pressure. The dogs were sensitized to horse serum by Weil's method.1 They were tested by intravenous injections of 0.5 to 2.0 cc. horse serum per kg. of body weight, about twenty-one days after the final sensitizing dose. The intracystic pressure was recorded by means of a glass catheter (perineal incision, male dogs). The abdomen was opened to avoid errors from changes in intraabdominal pressure. The following cystic reactions have thus far been recorded: 1. Typical Anaphylactic Shock. Arterial blood pressure falls precipitously to about 35 mm. Hg by the end of 45 seconds, gradually decreasing to about 25 mm. Hg by the end of 90 seconds. Recovery usually begins about the twelfth minute, the blood pressure being restored to normal in from 60 to 90 minutes. No recordable change in the intracystic pressure during the first 45 to 75 seconds. The intracystic pressure then gradually increases, usually reaching a maximum of from 25 to 50 mm. Hg by the end of two and a half minutes. Recovery immediately sets in, the intracystic pressure usually being reduced to normal by the seventh minute. No reactions were observed in normal controls. Assuming that the cystic reactions thus recorded are reliable indices to smooth muscle reactions in other parts of the body, one must conclude that in typical canine anaphylactic shock the smooth muscle structures are not thrown into contraction until the shock is fully established, as determined by the fall in arterial blood pressure. The smooth muscle reactions, therefore, apparently play no rôle in the initiation of the shock.