The effect of daily injections of cadmium on the systolic pressure of conscious rats.

The systolic blood pressure of nine conscious male Wistar rats of initial weight 170-200 gm was measured daily with a tail cuff. Once the blood pressure was stable, and the rats were used to being handled, six of them received intraperitoneal injections of 0.6 mg/kg of CdCl2 on five days of each week. The other three received comparable volumes of saline on five days of each week. The injections were carried out over a six-week period. During this period, none of the rats developed any significant change in systolic pressure as measured before the daily injections. By contrast, if the pressure was measured immediately after the injection, the pressure was measured immediately after the injection, the pressure rose abruptly, and remained elevated for several hours. Hypertonic saline had the same effect on one control rat and we speculated that transient hypertension could be due to mesenteric irritation rather than to some metabolic effect of the cadmium.