Water and salt consumption and suppression of angiotensin-induced thirst in rats after carotid glomectomy

Abstract

Carotid glomectomy in rats reduced daily water consumption and increased daily consumption of NaCl solution. Sham operation did not modify water and salt consumption. Intraperitoneal injection of angiotensin-II did not stimulate drinking motivation in the majority of rats subjected to carotid glomectomy. Injection of angiotensin-II to sham-operated and intact animals induced active consumption of both fluids during one hour. These results attest to the involvement of the carotid body in the regulation of consumption of water and sodium ions (the main elements of osmotic blood pressure) and the involvement of angiotensin-sensitive receptors of carotid body cells in the formation of thirst and salt appetite motivation, regulated by the renin-angiotensin system.

Comparative analysis of dipsogenic effects of systemic and intracerebral injection of angiotensin II to rats after carotid glomectomy

“…The mean daily volume (for 2 weeks) of NaCl solution drunk increased after the intervention in 5 of 7 rats; in 2 rats the mean volume of water drunk during a day surpassed that before surgery. The increase in the consumption of NaCl solution was in line with our previous data obtained under similar experimental conditions [7].…”

“…Glomectomy suppressed the typical dipsogenic effect of intraperitoneal A-II similarly to previous experiments [7]. Analysis of the dynamics of water and NaCl consumption over 1 h after intraperitoneal injection of A-II showed that these parameters were lower in glomectomized rats compared to shamoperated controls throughout the observation period (Fig.…”

“…Daily volumes of drunk fluid were measured in glomectomized (experimental) and sham-operated (control) animals over 2 weeks before and 2 weeks after the intervention. The methods were described in detail [2,7]. After 4 weeks the control and experimental animals were intraperitoneally injected with A-II (Sigma; 300 µg/ kg in 1 ml saline) and volumes of water and NaCl solution drunk over 60 min (min 0-10, 10-20, 20-40, and 40-60) after the injection were measured.…”

“…We found that bilateral surgical removal of the carotid bodies (carotid glomectomy; CGLE) in rats was associated with an increase in the mean daily consumption of NaCl solution. Thirst motivation and "salt appetite", usually induced by intraperitoneal injection of A-II, did not manifest or were significantly reduced in rats after CGLE [7,11,13]. The study of the characteristics of A-II-induced thirst after injection of A-II into the brain of glomectomized rats seems essential for understanding of the causes of suppressive effect of CGLE on the dipsogenic effect of A-II after systemic administration.…”

“…One of the major peripheral vascular chemoreceptors is the carotid body, whose receptors reacting to changes of gas constants, osmotic parameters of the blood, and other components of the water-salt balance send afferent signals about chemical composition of the blood into cerebral structures [1,4,8,10,12]. Discovery of A-IIsensitive receptors in the carotid body sensory cells [9,14] implies their involvement into the RAS-controlled regulation of water and mineral salt levels in the body [7]. We found that bilateral surgical removal of the carotid bodies (carotid glomectomy; CGLE) in rats was associated with an increase in the mean daily consumption of NaCl solution.…”