Faculté des sciences

Potassium restores vasorelaxation of resistance arterioles in non-hypertensive DOCA/salt fed mice

Wyss, C. ; Wang, Quing ; Golshayan, D. ; Nussberger, J. ; Burnier, M. ; Lehr, H.A. ; Schaefer, S.C.

In: Microvascular Research, 2012, vol. 84, no. 3, p. 340–344

Background: Potassium-enriched diets exert renal and cardiovascular protective effects, but the underlying mechanisms are largely unknown.Methods: Using the dorsal skinfold chamber model for intravital microscopy, we examined endothelium-dependent vasorelaxation of precapillary resistance arterioles in response to acetylcholine or the NO donor SNAP in awake mice. Experiments were performed in... Plus

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    Summary
    Background: Potassium-enriched diets exert renal and cardiovascular protective effects, but the underlying mechanisms are largely unknown.Methods: Using the dorsal skinfold chamber model for intravital microscopy, we examined endothelium-dependent vasorelaxation of precapillary resistance arterioles in response to acetylcholine or the NO donor SNAP in awake mice. Experiments were performed in uni-nephrectomized one renin gene (Ren-1c) C57BL/6 mice (control group) and in mice having received a continuous administration of deoxycorticosterone acetate and a dietary supplementation of 1% sodium chloride for 8 weeks (DOCA/salt group). An additional group of DOCA/salt treated animals received a dietary supplement of 0.4% KCl for 3 weeks prior to the experiments (DOCA/salt + potassium group).Results: DOCA/salt treatment for 8 weeks resulted in hypokalemia, but blood pressure remained unchanged. In DOCA/salt mice, relaxation of resistance arterioles was blunted in response to acetylcholine, and to a lesser extent to SNAP, suggesting endothelial dysfunction. Endothelium-dependent vasorelaxation was restored by the potassium‐enriched diet.Conclusion: This study is the first to demonstrate a protective effect of potassium on endothelium-dependent vasorelaxation in the absence of confounding anti-hypertensive effects, as observed in most animal models and the clinical situation. We propose that the known cardio- and nephro-protective effects of potassium might – at least in part – be mediated by the salutary effects on endothelium-dependent arteriolar relaxation.