Vascular smooth muscle Gq signaling is involved in high blood pressure in both induced renal and genetic vascular smooth muscle-derived models of hypertension

Vascular smooth muscle Gq signaling is involved in high blood pressure in both induced renal and genetic vascular smooth muscle-derived models of hypertension. Am J Physiol Heart Circ Physiol 293: H3072-H3079, 2007. First published September 14, 2007; doi:10.1152/ajpheart.00880.2007. - More than 30% of the US population has high blood pressure ( BP), and less than a third of people treated for hypertension have it controlled. In addition, the etiology of most high BP is not known. Having a better understanding of the mechanisms underlying hypertension could potentially increase the effectiveness of treatment. Because Gq signaling mediates vasoconstriction and vascular function can cause BP abnormalities, we were interested in determining the role of vascular smooth muscle (VSM) Gq signaling in two divergent models of hypertension: a renovascular model of hypertension through renal artery stenosis and a genetic model of hypertension using mice with VSM-derived high BP. Inhibition of VSM Gq signaling attenuated BP increases induced by renal artery stenosis to a similar extent as losartan, an ANG II receptor blocker and current antihypertensive therapy. Inhibition of Gq signaling also attenuated high BP in our genetic VSM-derived hypertensive model. In contrast, BP remained elevated 25% following treatment with losartan, and prazosin, an alpha(1)-adrenergic receptor antagonist, only decreased BP by 35%. Inhibition of Gq signaling attenuated VSM reactivity to ANG II and resulted in a 2.4-fold rightward shift in EC50. We also determined that inhibition of Gq signaling was able to reverse VSM hypertrophy in the genetic VSM-derived hypertensive model. These results suggest that Gq signaling is an important signaling pathway in two divergent models of hypertension and, perhaps, optimization of antihypertensive therapy could occur with the identification of particular G(q)-coupled receptors involved.