Water drinking induced in sheep by angiotensin: A physiological or pharmacological effect?

Abraham, Suzanne; Baker, Rodney; Blaine, Edward H.; Denton, D. A.; McKinley, Michael J.

doi:10.1037/h0076405

Cited by 87 publications

(27 citation statements)

References 25 publications

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“…Only very small amounts of ANG I were present in the CSF of dogs and rats, while CSF ANG II concentrations were comparable to those in plas ma. The same or somewhat lower ANG II levels were re ported for CSF of men [54,59] and sheep [1). Depending upon the RIA procedure, CSF ANG II levels of dogs were found by others to be undetectable or within the range re ported here [50], while even higher amounts were measured in a further study [33].…”

Section: Discussionmentioning

confidence: 70%

Components of the Renin-Angiotensin System in the Cerebrospinal Fluid of Rats and Dogs with Special Consideration of the Origin and the Fate of Angiotensin II

et al. 1980

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From the in vitro and in vivo measurements of the components of the renin-angiotensin system (RAS) in the cerebrospinal fluid (CSF) of rats and dogs, it was concluded that angiotensin II (ANG II) is not generated within the CSF in significant amounts, since renin was found to be unmeasurable in CSF under most circumstances. The specific concentrations of angiotensinogen and of converting enzyme (CE) were high. Angiotensin I (ANG I) concentrations were low in CSF, while ANG II levels were comparable to those measured in plasma under control conditions. Neither ANG I nor ANG II penetrated from the blood into the brain ventricles of rats, provided that no unrealistically high doses of ANG II were administered intravenously. This holds true even if high blood pressure increases were induced by intravenous ANG II infusion in deoxycorticosterone acetate (DOCA) and salt-treated rats. However, increased ANG II concentrations were measured in CSF perfusate, when the blood-brain barrier (BBB) was opened by the intracarotid injection of a hyperosmolar urea solution. The brain ventricular perfusion of increasing concentrations of ANG II revealed constant recovery of less than 40%. CSF did not contain angiotensinase activity, but ANG II degradation was high in some periventricular regions. ANG II, the ANG II antagonist saralasin, and the CE inhibitor captopril, respectively, escaped from CSF into circulation when high doses of these substances were applied intraventricularly. We conclude that ANG II in the CSF does not originate from and is not related to plasma ANG II. It is probably not generated within the CSF. ANG II may be synthetized in the brain tissue and be released into the brain ventricles where its rapid degradation occurs in contact with circumventricular structures.

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Section: Discussionmentioning

confidence: 70%

Components of the Renin-Angiotensin System in the Cerebrospinal Fluid of Rats and Dogs with Special Consideration of the Origin and the Fate of Angiotensin II

et al. 1980

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“…have been described in cerebrospinal fluid of different species (Finkielman, Fischer-Ferraro, Diaz, Goldstein & Nahmod, 1972;Saad, Epstein, Simpson & Camargo, 1975;Abraham, Baker, Blaine, Denton & McKinley, 1975;Ganten et al, 1976a). They have not been fully characterized.…”

Section: Cerebrospinal Fluid and Choroid P/euusmentioning

confidence: 93%

Tissue iso-renins

et al. 1976

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1.Several extrarenal tissues contain enzymes which are similar to kidney renin: they hydrolyse angiotensinogen to form angiotensin I ; they have characteristic substrate specificity; the physicochemical properties of kidney renin and of extrarenal tissue iso-renin are similar.2. Results indicate that tissue iso-renins are part of a complex enzyme system with mainly local function. A possible biological role has been demonstrated in brain, adrenal gland and tissue culture.

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“…During water deprivation, the number of ANG receptors increase in the SFO, OVLT, MnPO and PVN (Nazarali et al 1987). The role of ANG in the central regulation of water intake in rats and sheep has been widely reported (Abraham et al 1975;Fitzsimons 1979;Blair-West et al 1988;Brehaus and Chimoskey 1990;Weisinger et al 1997). In these animals, injection of ANG into the lateral ventricle increased thirst sensations, vasopressin secretion, and sodium intake (Ramsey and Ganong 1977;Weisinger et al 1986a).…”

Section: Mots Clésmentioning

confidence: 99%

The role of angiotensin II in the central regulation of feed intake in sheep

Sunagawa¹,

Weisinger²,

Purcell³

et al. 2001

Can. J. Anim. Sci.

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[215][216][217][218][219][220][221]. The objective was to determine the role of Angiotensin II (ANG) in the central regulation of feed intake by ruminants. As a control treatment, artificial cerebrospinal fluid (CSF) was given (over a period of 98.5 h) as a continuous intracerebroventricular (ICV) infusion (0.2 mL h -1 ) into the lateral ventricle of ewes (n = 5). Approximately 9 d later, the infusion was repeated with the same ewes, but the CSF contained ANG (25 µg mL -1 ). The ewes were fed dried alfalfa chaff for 2 h once daily and both water and a 0.5 M NaCl solution were available ad libitum (except that water intake was restricted on the first day of ANG infusion). Infusion of ANG resulted in severe thirst that persisted when water intake was restricted to an amount equal to voluntary intake during the control infusion. Furthermore, when ewes had ad libitum access to water, consumption during ANG infusion was 1.4 to 2.8-fold greater than that during CSF infusion (P < 0.01). Compared with CSF infusion, ANG infusion decreased eating rates by an average of 46.5% (range, 31.8-62.6%; P < 0.01) and feed intake by 25.0% (5.4-48.1%; P < 0.01), and increased salt intake by 273.8% (124.0-417.6%; P < 0.01). We concluded that ANG produced thirst sensations in the brain, resulting in excessive water intake that caused ruminal distension and significantly reduced feed intake. La recherche devait établir le rôle de l'angiotensine II (ANG) dans la régulation de la prise alimentaire par le système nerveux central chez les ruminants. Comme traitement témoin, on a infusé en continu 0,2 mL h -1 de liquide céphalorachidien artificiel (CSF) pendant 98,5 h par voie intracérébroventriculaire (ICV) dans le ventricule latéral de brebis (n = 5). Neuf jours plus tard environ, on a répété l'infusion chez les mêmes animaux, mais avec du CSF contenant de l'ANG (25 µg mL -1 ). Les brebis ont ensuite reçu de la paille de luzerne sèche pendant deux heures chaque jour ainsi que de l'eau et une solution de NaCl 0,5 M ad libitum (sauf le premier jour de l'infusion d'ANG, où l'on a restreint la consommation d'eau). L'infusion d'ANG entraîne une soif intense qui n'a pu être étanchée quand la quantité d'eau était limitée à celle volontairement absorbée par les animaux après infusion de la solution témoin. Par ailleurs, lorsqu'elles peuvent boire à satiété, les brebis consomment de 1,4 à 2,8 fois plus d'eau qu'après l'infusion de CSF (P < 0,01). Comparativement à celle de CSF, l'infusion d'ANG réduit l'indice de consommation d'en moyenne 46,5 % (fourchette de 31,8 à 62,6 %; P < 0,01) et la prise alimentaire de 25,0 % (de 5,4 à 48,1 %; P < 0.01), tandis que l'absorption de sel augmente de 273,8 % (de 124,0 à 417,6 %; P < 0,01). Les auteurs en concluent que l'ANG provoque une grande sensation de soif dans le cerveau, ce qui entraîne une consommation excessive d'eau conduisant à la distension du rumen et à une plus faible prise alimentaire.

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Water drinking induced in sheep by angiotensin: A physiological or pharmacological effect?

Cited by 87 publications

References 25 publications

Components of the Renin-Angiotensin System in the Cerebrospinal Fluid of Rats and Dogs with Special Consideration of the Origin and the Fate of Angiotensin II

Components of the Renin-Angiotensin System in the Cerebrospinal Fluid of Rats and Dogs with Special Consideration of the Origin and the Fate of Angiotensin II

Tissue iso-renins

The role of angiotensin II in the central regulation of feed intake in sheep

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