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The vascular Na+-K+ pump in experimental hypertension
1Department of Medicine, University of Alabama, Birmingham 35294.
Hypertension (Dallas, Tex. : 1979)
|November 1, 1987
Summary
This study found no evidence that circulating ouabainlike factors significantly affect arteriolar function in early or chronic hypertension. These findings suggest other mechanisms may be involved in hypertensive vascular responses.
Area of Science:
- Cardiovascular Physiology
- Renal Hypertension
- Endocrinology
Background:
- Hypertension is associated with circulating factors that may affect vascular tone.
- Ouabainlike factors are implicated in regulating sodium-potassium pump activity and vascular function.
Purpose of the Study:
- To investigate the role of circulating ouabainlike factors in arteriolar function during early and chronic one-kidney, one clip (1K1C) hypertension in rats.
Main Methods:
- Vascular responses were measured in isolated hindlimb vascular beds of anesthetized rats with 1K1C hypertension.
- Norepinephrine dose-response curves were assessed with and without ouabain or desimipramine to block neural norepinephrine uptake.
Main Results:
- No significant changes in norepinephrine thresholds or ED50 values were observed in hypertensive rats compared to controls.
- Ouabain-induced shifts in norepinephrine dose-response curves were unchanged, indicating no significant inotropic effect of ouabainlike factors on arterioles.
Conclusions:
- Circulating ouabainlike factors do not appear to exert physiologically significant inotropic effects on arterioles in vivo during early or chronic 1K1C hypertension.
- Further research is needed to explore potential modifications of vascular responses by induced Na+-K+-adenosine triphosphatase activity.