Expression of endothelin, endothelin type A receptor, isoforms of nitric oxide synthase, and angiotensin receptors in endothelin type B receptor deficient mice

Abstract

Endothelin‐1 (ET‐1) is involved in the control of renal vessel contractions by acting on endothelin type A (ETA) and type B (ETB) receptors. Several studies indicate an interaction of ET‐1 with the angiotensin system; which includes modulation of receptor expression. The aim of this study was to determine the influence of ETB receptor deficiency on the expression of ET‐1, ETA receptors, nitric oxide synthases (NOS) as well as angiotensin receptors (AT) in preglomerular vessels and kidneys of ETB(‐/‐) mice. ETA mRNA expression, determined by real time PCR, was decreased in preglomerular vessels compared to wild type mice (ETB(+/+)). ETA mRNA and protein were also diminished in whole kidney preparations in ETB(‐/‐) mice. The endothelial NOS (eNOS) mRNA was less expressed in preglomerular vessels. No significant differences were found for mRNA expression of eNOS, nNOS, and iNOS in whole kidney preparations. AT1 and AT2 receptor mRNA in the kidney did not differ between ETB(‐/‐) and ETB(+/+). As shown by western blotting analysis the ET‐1 protein was stronger expressed in the kidneys of ETB(‐/‐) The results of ET‐1 and ETA expression confirm earlier findings of a clearance function of the ETB receptor and modulation of ETA expression by ET‐1. Moreover, ET receptor expression/function seems to influence eNOS mRNA expression in renal arterioles.