AT₁ angiotensin II receptor and novel non-AT₁, non-AT₂ angiotensin II/III binding site in brainstem cardiovascular regulatory centers of the spontaneously hypertensive rat.

The authors investigated two aims in this study.  The first aim is to compare AT1 receptor binding in the RVLM and other cardiovascular control regions between SHR and WKY.  They hypothesize that AT1 receptors are more abundant in the RVLM of SHR. The second aim is to compare the relative expression of the binding sites between SHR and WKY in the DMM, RVLM and CVLM. They hypothesize that the binding site is differentially expressed in hypertensive rats.  Similar to their previous studies the authors used autoradiography to determine the receptor binding. They found an increased AT1 receptor binding in DMM (dorsalmedial medulla), CVLM and RVLM of SHR compared to WKY.  However, non-AT1, non-AT2 receptor, Ang II and Ang III binding sites were decreased in the RVLM and DMM of SHR. The increased AT1 receptor binding the RVLM could contribute to the hypertension of SHR.  The authors believe that reduced expression of non-AT1 and non-AT2 binding sites in the RVLM may be involved in the reducing the blood pressure through its interaction with Ang II and Ang III.

-Madhan