Increased expression and function of vascular alpha1D-adrenoceptors may mediate the prohypertensive effects of angiotensin II.

The peptide Angiotensin II (Ang II), part of the renin-angiotensin system (RAS), participates in the control of systemic arterial pressure. Ang II participates in increasing smooth muscle tone, and its positive effects on smooth muscle cell DNA synthesis are inhibited by treatment with prazosin, an alpha(1)-adrenoceptor agonist. Ang II also induces the expression of alpha(1)-adrenoceptor, especially the alpha(1D) subtype. Other findings suggest that the molecular signals activated by Ang II and by alpha(1D)-adrenoceptor might interweave, thus leading to the augmentation of smooth muscle tone and hypertension.