Decrease in [3H]ouabain binding sites in heart and brain from spontaneously hypertensive rats

1981 ◽  
Vol 37 (5) ◽  
pp. 492-493 ◽  
Author(s):  
R. Gheyouche ◽  
A. Uzan ◽  
G. Le Fur ◽  
M. Corgier
Keyword(s):  
Binding Sites ◽  
Spontaneously Hypertensive Rats ◽  
Hypertensive Rats ◽  
Ouabain Binding ◽  
Spontaneously Hypertensive

Vasopressin receptors and inositol trisphosphate production in blood vessels of spontaneously hypertensive rats

1989 ◽  
Vol 67 (3) ◽  
pp. 232-239 ◽  
Author(s):  
Richard Larivière ◽  
Johanne Baribeau ◽  
Jean St-Louis ◽  
Ernesto L. Schiffrin
Keyword(s):  
Blood Pressure ◽  
Phospholipase C ◽  
Binding Sites ◽  
Spontaneously Hypertensive Rats ◽  
Pressor Response ◽  
Inositol Trisphosphate ◽  
Normal Density ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Phosphoinositide Breakdown

To understand the regulation of vasopressin (AVP) receptors in spontaneous hypertension, we investigated the pressor response of AVP in the perfused mesenteric vasculature, AVP binding sites in the membrane preparation of the same vascular bed, and the production of inositol trisphosphate (InsP3) stimulated by AVP in the aorta of spontaneously hypertensive rats (SHR), Wistar–Kyoto rats (WKY), and Wistar rats (WR) at different ages (4–16 weeks). Plasma AVP concentrations were similar in SHR, WKY, and WR at all ages. The density of AVP vascular binding sites was significantly higher in WKY than in SHR and WR at 12 weeks. Receptor affinity was similar in all strains. The pressor response of the mesenteric vasculature to AVP was similar in the three strains of rats at 4 weeks (prehypertensive stage) and increased progressively in SHR compared with WKY and WR at 8 and 12 weeks of age by 43 and 35%, respectively, and by more than 80% at 16 weeks of age (established hypertensive stage). There was no difference in vascular sensitivity to AVP. A significantly increased pressor response to a supramaximal dose of norepinephrine was also found at 16 weeks in SHR, but not in younger rats. InsP3 production in the aorta in response to AVP was increased in SHR at 8, 12, and 16 weeks, compared with WKY and WR. These results suggest that the vascular response to AVP is increased in SHR, in spite of decreased or normal density of binding sites compared with WKY or WR. The increased responsiveness to AVP in SHR may be mediated in part by the enhanced activity of AVP receptor-coupled phospholipase C, resulting in increased membrane phosphoinositide breakdown and inositol trisphosphate production, which may play a role in the elevation of blood pressure in SHR.Key words: vascular reactivity, vasopressin binding sites, phosphoinositide breakdown, phospholipase C, high blood pressure.

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