Renal actions of atrial natriuretic peptide in spontaneously hypertensive rats: the role of nitric oxide as a key mediator.

Atrial natriuretic peptide (ANP) is an important regulator of blood pressure (BP). One of the mechanisms whereby ANP impacts BP is by stimulation of nitric oxide (NO) production in different tissues involved in BP control. We hypothesized that ANP-stimulated NO is impaired in the kidneys of spontaneously hypertensive rats (SHR) and this contributes to the development and/or maintenance of high levels of BP. We investigated the effects of ANP on the NO system in SHR, studying the changes in renal nitric oxide synthase (NOS) activity and expression in response to peptide infusion, the signaling pathways implicated in the signaling cascade that activates NOS, and identifying the natriuretic peptide receptors (NPR), guanylyl cyclase receptors (NPR-A and NPR-B) and/or NPR-C, and NOS isoforms involved. In vivo, SHR and Wistar-Kyoto rats (WKY) were infused with saline (0.05 ml/min) or ANP (0.2 μg·kg−1·min−1). NOS activity and endothelial (eNOS), neuronal (nNOS), and inducible (iNOS) NOS expression were measured ...