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

Abstract

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.

Associative learning contributes to the increased water intake observed after daily injections of angiotensin II

“…Specifically, pairing injections of AngII with gastric infusion of water was not sufficient to condition the increased appetition observed in rats after pairing AngII and normal access to water. Consistent both with earlier work showing intact drinking and satiation responses in a rat model of gastric bypass [13] and with the present finding that the altered drinking is a function of burst size differences, but not changes in burst number, the collective indication is that postingestive feedback alone is not sufficient to condition increased appetition to repeated AngII. This suggests that something about the orosensory experience of drinking or some other facet of the drinking experience is required for both intake termination and the increased appetition observed here.…”

Body weight-dependent and independent improvement in lipid metabolism after Roux-en-Y gastric bypass in ApoE*3Leiden.CETP mice

“…This indicated that RYGB surgery and caloric restriction in BWm mice did not affect water intake, and indicated that mice were not dehydrated. These data are consistent with earlier data by Marshall et al [34] who showed that water intake seems to be largely c) differ from each other at the P < 0.05 levels by post hoc Bonferroni adjustment when significant intergroup differences were found by oneway ANOVA (d-f) unaffected in RYGB-operated rats, and suggest that differences in hydration status did not contribute to various changes observed in the RYGB group.…”