Effects of a non-peptide angiotensin receptor antagonist on drinking and blood pressure responses to centrally administered angiotensins in the rat

Both angiotensin II (ANG II) and angiotensin III (ANG III) administered centrally produce drinking and increases in blood pressure. The recent characterization of two subtypes for the ANG II receptor, the AT1 and the AT2, raises the questions of whether drinking and pressor responses to ANG II can be separated pharmacologically and whether ANG III acts via the same receptor subtype. Therefore, the current study examined drinking and blood pressure responses to ANG II and ANG III administered centrally in adult male Sprague-Dawley rats in the presence or absence of a selective AT1 receptor antagonist. Blockade of the AT1 receptor abolished both drinking and pressor responses to ANG II and ANG III. However, drinking to the cholinergic agonist, carbachol, was unaffected. These results demonstrate that centrally administered ANG II and ANG III increase both water intake and blood pressure via the AT1 receptor subtype.