ANP and BNP Responses to Dehydration in the One-Humped Camel and Effects of Blocking the Renin-Angiotensin System

Abstract

The objectives of this study were to investigate and compare the responses of atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) in the circulation of hydrated, dehydrated, and dehydrated losartan - treated camels; and to document the cardiac storage form of B-type natriuretic peptide in the camel heart. Eighteen male camels were used in the study: control or hydrated camels (n = 6), dehydrated camels (n = 6) and dehydrated losartan-treated camels (n = 6) which were dehydrated and received the angiotensin II (Ang II) AT-1 receptor blocker, losartan, at a dose of 5 mg/kg body weight intravenously for 20 days. Control animals were supplied with feed and water ad-libitum while both dehydrated and dehydrated-losartan treated groups were supplied with feed ad-libitum but no water for 20 days. Compared with time-matched controls, dehydrated camels exhibited a significant decrease in plasma levels of both ANP and BNP. Losartan-treated camels also exhibited a significant decline in ANP and BNP levels across 20 days of dehydration but the changes were not different from those seen with dehydration alone. Size exclusion high performance liquid chromatography of extracts of camel heart indicated that proB-type natriuretic peptide is the storage form of the peptide.We conclude first, that dehydration in the camel induces vigorous decrements in circulating levels of ANP and BNP; second, blockade of the renin-angiotensin system has little or no modulatory effect on the ANP and BNP responses to dehydration; third, proB-type natriuretic peptide is the storage form of this hormone in the heart of the one-humped camel.

Comparative physiological, morphological, histological, and AQP2 immunohistochemical analysis of the Arabian camels (Camelus dromedarius) and oxen kidney: Effects of adaptation to arid environments

“…The RCs and glomeruli in dromedary kidneys are larger than those recognized in the kidneys of the ox. These findings were supported by the approved idea that dromedaries suffering dehydration have a 73% reduction of the reuptake of sodium from tubular lumens resulting in concentrating the urine and better preserving water in contrast to the bovine kidney which is unable to form concentrated urine (Rowen and Wilke, 2009;Adem et al, 2013). In this study, PCTs were lined with simple cuboidal epithelium and found larger in the case of dromedaries than oxen.…”

A comparison of physiological and transcriptome responses to water deprivation and salt loading in the rat supraoptic nucleus

“…There is also a significant difference between the WD and SL with respect to both AVP and OXT, the former being higher and the latter lower after SL than WD. Circulating ANP levels are lower than those under EU conditions (2). Although ANP levels correlate well with AVP and hypertonicity, ANP is regulated principally by plasma volume, whereas AVP is primarily modulated by a change in plasma osmolality and secondarily by volume change (27).…”

NT‐proBNPand cardiac troponin I concentrations in dogs with tick paralysis caused byIxodes holocyclus

“…23 As such, our results suggested that myocardial wall stress was reduced in dogs with tick paralysis, regardless of their state of respiratory compromise. [42][43][44][45][46] Future studies could investigate the presence or absence of significant dehydration in dogs with tick paralysis using additional indicators of hydration status such as urine specific gravity and total serum protein concentration, 47 and body weight at admission and after recovery. Furthermore, many dogs with tick paralysis vomit or regurgitate, possibly also contributing to a reduction in preload.…”

“…It has been shown in dogs and a range of other species that dehydration in the acute setting similarly decreases plasma natriuretic peptide concentrations. [42][43][44][45][46] Future studies could investigate the presence or absence of significant dehydration in dogs with tick paralysis using additional indicators of hydration status such as urine specific gravity and total serum protein concentration, 47 and body weight at admission and after recovery.…”