Roux-en-Y gastric bypass does not affect daily water intake or the drinking response to dipsogenic stimuli in rats

Bariatric surgery is currently the most effective treatment for severe obesity, and Roux-en-Y gastric bypass (RYGB) is the most common approach in the United States and worldwide. Many studies have documented the changes in body weight, food intake, and glycemic control associated with the procedure. Although dehydration is commonly listed as a postoperative complication, little focus has been directed to testing the response to dipsogenic treatments after RYGB. Accordingly, we used a rat model of RYGB to test for procedure-induced changes in daily water intake and in the response to three dipsogenic treatments: central administration of ANG II, peripheral injection of hypertonic saline, and overnight water deprivation. We did not find any systematic differences in daily water intake of sham-operated and RYGB rats, nor did we find any differences in the response to the dipsogenic treatments. The results of these experiments suggest that RYGB does not impair thirst responses and does not enhance any satiating effect of water intake. Furthermore, these data support the current view that feedback from the stomach is unnecessary for the termination of drinking behavior and are consistent with a role of orosensory or postgastric feedback.