Increased sensitivity of the osmotic control of vasopressin in sheep with deoxycorticosterone acetate-induced hypertension

Brooks, David P.; Share, Leonard; Crofton, J. T.; Guthe, C C; Ling, William; Bohr, D. F.

doi:10.1677/joe.0.1070309

Cited by 5 publications

(5 citation statements)

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“…The failure to observe any difference in the osmotic responsiveness of HNS explants from 5-, 8-, and 18-week-old SHR and WKY to a 12 mosm/kg H 2 O stimulus further supports the interpretation that VP release is appropriately responsive to osmotic stimulation in both young and chronically hypertensive SHR and alleviates any concern that differential blood pressure responses to the hypertonic saline in the two strains contribute to the in vivo results. The appropriate osmosensitivity of the VP system in SHR also contrasts with the enhanced osmosensitivity observed in DOCA hypertension 6 and the enhanced plasma VP levels observed in hypertensive men with a high salt intake. 7 Thus, enhanced osmosensitivity of VP release is not observed in all forms of hypertension.…”

Section: Figure 2 Relationship Between Serum Sodium (Sna) and Serum mentioning

confidence: 79%

“…1 The present studies were performed to evaluate whether the VP and renin systems show altered responsiveness to extracellular fluid osmolality and sodium concentration, respectively. VP release is stimulated by increased plasma osmolality detected by hypothalamic osmoreceptors, 2 ' 3 while renin release is suppressed by elevated plasma sodium due to direct renal effects 4 and, possibly, as a central nervous system-mediated response to changes in cerebrospinal fluid (CSF) sodium concentration.5 Enhanced VP sensitivity to increases in osmolality have been observed in sheep with deoxycorticosterone acetate (DOCA)-induced hypertension, 6 and a correlation between elevated sodium intake and elevated plasma VP exist in hypertensive men, but not normotensive men, over 50 years of age. …”

mentioning

confidence: 99%

“…5 Enhanced VP sensitivity to increases in osmolality have been observed in sheep with deoxycorticosterone acetate (DOCA)-induced hypertension, 6 and a correlation between elevated sodium intake and elevated plasma VP exist in hypertensive men, but not normotensive men, over 50 years of age.…”

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confidence: 99%

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Osmotic regulation of vasopressin and renin in spontaneously hypertensive rats.

et al. 1987

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SUMMARY Abnormalities in the vasopressin and renin systems have been reported in spontaneously hypertensive rats (SHR). Therefore, studies were performed to evaluate the responsiveness of these systems to changes in plasma osmolality and sodium concentration. These variables were manipulated in vivo by intraperitoneal administration of distilled water, isotonic saline, or hypertonic saline to 8-and 18-week-old SHR and normotensive Wistar-Kyoto rats (WKY). Animals were decapitated 30 minutes later, and trunk blood was collected. The hypertonic saline injections resulted in an increase in plasma osmolality and serum sodium at both ages (p< 0.001). Serum vasopressin was higher in all groups of animals receiving hypertonic saline (1200 mosm/kg H 2 O; p<0.05), but the magnitude of increase was not significantly different in the SHR and WKY at either age. Serum renin activity was lower in SHR than in WKY following acute decreases in serum sodium at 8 weeks, but it was the same for both strains at 18 weeks. Both kidney renin content and concentration were lower in SHR than in WKY at 18 weeks but not at 8 weeks. Therefore, the suppressed renin response to acute osmotic challenge in 8-week-old SHR is not the consequence of reduced kidney renin content. The vasopressin response to osmotic stimulation also was evaluated in vitro using hypothalamoneurohypophyseal explants obtained from 5-, 8-, and 18-week-old SHR and WKY. Vasopressin release was significantly increased in response to an increase in osmolality of 12 mosm/kg H 2 O in all groups (p<0.01), but the response was not significantly different in explants of SHR and WKY at any age. The comparable response of the vasopressin system to osmotic challenge in SHR and WKY is in contrast to the previously observed hyperresponsiveness of the vasopressin system to an acute decrease in plasma volume and to acetylcholine in vitro. Thus, it indicates that the previously observed hyperresponsiveness of the vasopressin system is specific to the stimulus rather than a generalized phenomenon. (Hypertension 10: 476-483, 1987) KEY WORDS • hypertension • renin-angiotensin system • renal renin content A LTERATIONS in the responsiveness of the /\ vasopressin (VP) and renin systems to an A. \. acute decrease in plasma volume have been observed in spontaneously hypertensive rats (SHR). Specifically, during the development of hypertension in SHR the VP response to an acute decrease in plasma volume is exaggerated, but the renin response is suppressed when compared with that in age-matched nor- Supported by a grant from the National Heart, Lung, and Blood Institute (R01-HL-28172) and a Research Career Development Award (K01-HL-00966) to Dr. Blair.Address for reprints: Dr. Celia D. Sladek, Department of Neurology, Box 603, University of Rochester, 601 Elmwood Avenue, Rochester, NY 14642.Received December 22, 1986; accepted June 5, 1987. motensive Wistar-Kyoto rats (WKY). 1 The present studies were performed to evaluate whether the VP and renin systems show altered responsiveness to extr...

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Section: Figure 2 Relationship Between Serum Sodium (Sna) and Serum mentioning

confidence: 79%

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confidence: 99%

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Osmotic regulation of vasopressin and renin in spontaneously hypertensive rats.

et al. 1987

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“…This could occur in response to a sustained increase in osmolality due to reduced water intake, but it could also result from enhanced mineralocorticoid secretion, since AVP concentrations rise after about 3 weeks in sheep bearing deoxycorticosterone implants (Brooks, Share, Crofton et al 1985). However, the reason that a similar pattern of response is not seen during acute stress seems to be that cortisol raises the osmotic threshold for AVP release (Aubry, Nankin, Moses & Streeten, 1965).…”

Section: Discussionmentioning

confidence: 99%

Endocrine and behavioural factors affecting water balance in sheep subjected to isolation stress

Parrott¹,

Thornton²,

Forsling³

et al. 1987

Journal of Endocrinology

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The effect of stress on drinking, water balance and endocrine profile was studied using ten castrated rams. Individual sheep were exposed to 30-h periods of total isolation (psychological stress) or physical separation from their social group (control). Plasma was analysed for haematocrit, osmolality, electrolyte levels and concentrations of cortisol and arginine vasopressin. Isolation stress significantly reduced water intake, increased haematocrit and plasma concentration of cortisol, but did not alter osmolality or vasopressin concentration. The physiological effects of this self-imposed water restriction contrast with those obtained by depriving the sheep of water for 24 h under conditions that were not stressful, i.e. by keeping them grouped together. These results suggest that cortisol may act to defend plasma volume in sheep exposed to acute stress. The results also indicate that vasopressin probably should not be considered to be a 'stress hormone' in the sheep.

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“…Consistent with the latter supposition, urinary sodium excretion in sheep given 3–4 day infusions of aldosterone was almost entirely blocked by the acute CNS administration of a low sodium cerebrospinal fluid during mineralocorticoid escape ( 129 ). Further, mineralocorticoids also augment the osmotic sensitivity of ADH secretion ( 130 ).…”

Section: Cns Natriuresismentioning

confidence: 99%

Natriuretic Hormones, Endogenous Ouabain, and Related Sodium Transport Inhibitors

Hamlyn

2014

Front. Endocrinol.

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The work of deWardener and colleagues stimulated longstanding interest in natriuretic hormones (NHs). In addition to the atrial peptides (APs), the circulation contains unidentified physiologically relevant NHs. One NH is controlled by the central nervous system (CNS) and likely secreted by the pituitary. Its circulating activity is modulated by salt intake and the prevailing sodium concentration of the blood and intracerebroventricular fluid, and contributes to postprandial and dehydration natriuresis. The other NH, mobilized by atrial stretch, promotes natriuresis by increasing the production of intrarenal dopamine and/or nitric oxide (NO). Both NHs have short (<35 min) circulating half lives, depress renotubular sodium transport, and neither requires the renal nerves. The search for NHs led to endogenous cardiotonic steroids (CTS) including ouabain-, digoxin-, and bufadienolide-like materials. These CTS, given acutely in high nanomole to micromole amounts into the general or renal circulations, inhibit sodium pumps and are natriuretic. Among these CTS, only bufalin is cleared sufficiently rapidly to qualify for an NH-like role. Ouabain-like CTS are cleared slowly, and when given chronically in low daily nanomole amounts, promote sodium retention, augment arterial myogenic tone, reduce renal blood flow and glomerular filtration, suppress NO in the renal vasa recta, and increase sympathetic nerve activity and blood pressure. Moreover, lowering total body sodium raises circulating endogenous ouabain. Thus, ouabain-like CTS have physiological actions that, like aldosterone, support renal sodium retention and blood pressure. In conclusion, the mammalian circulation contains two non-AP NHs. Identification of the CNS NH should be a priority.

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Increased sensitivity of the osmotic control of vasopressin in sheep with deoxycorticosterone acetate-induced hypertension

Cited by 5 publications

References 14 publications

Osmotic regulation of vasopressin and renin in spontaneously hypertensive rats.

Osmotic regulation of vasopressin and renin in spontaneously hypertensive rats.

Endocrine and behavioural factors affecting water balance in sheep subjected to isolation stress

Natriuretic Hormones, Endogenous Ouabain, and Related Sodium Transport Inhibitors

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