Role of endothelin in the pathogenesis of experimental hypertension in rats

The plasma endothelin (ET) level in SHR and 2K1C hypertension animal models and its vasoconstrictive effect in their renal and tail arteries were studied. The results demonstrated that there was no difference of plasma ET level between the hypertensive groups SHR, 2K1C and the normotensive control groups WKY and SD, while the vasoconstrictive effect of ET in SHR was were more predominant than that in WKY. The EC50 of the renal and tail arteries in SHR (0.8912 +/- 0.4398 x 10(-8) M, 0.6103 +/- 0.2633 x 10(-8) M) were apparently lower than those in WKY (1.711 +/- 0.7327 x 10(-8) M, 1.2667 +/- 0.6129 x 10(-8) M, (P less than 0.05); but there was no difference between 2K1C and SD rats. The four groups of animals mentioned above exhibited no differences of such effects in response to norepinephrine (NA). The results suggested that the increased arteriole sensitivity to ET was an important factor in the pathogenesis of hypertension in SHR.