Description:
<jats:sec><jats:label /><jats:p>We recently reported the expression of receptors for the hormone angiotensin II [Ang II] in isolated nuclei of the sheep kidney. The renal cortex contained predominantly AT<jats:sub>2</jats:sub> receptors [~70%], while the renal medulla expressed essentially the AT<jats:sub>1</jats:sub> subtype [>90%]. The present study examined their functional roles in cortical nuclei of adult sheep. Nuclei were isolated from kidneys of adult (1.5 yr old) sheep by Optiprep density gradient and loaded with the fluorescence dye difluorofluorescein diacetate (DAF) to assess the production of nitric oxide (NO). Ang II (1 nM) significantly increased DAF fluorescence above control (80 +/‐ 11%; P<0.001; N=4); DAF stimulation was abolished by either the AT<jats:sub>2</jats:sub> antagonist PD123319 (1µM, P>0.05 vs. control) or the NO synthase inhibitor L‐NAME (1mM, P>0.05 vs. control). Treatment with AT<jats:sub>1</jats:sub> receptor antagonist losartan (1µM) did not alter Ang II‐induced NO generation (P>0.05 vs. Ang II). Protein analysis of isolated cortical nuclei revealed a prominent band for both eNOS/NOSIII (135kDa) and the principal NO receptor soluble guanylate cyclase‐β (sGC, 70kDa). We demonstrate that the nuclear AT<jats:sub>2</jats:sub> receptor subtype is functionally linked to NO generation and confirm the expression of eNOS and sGC in sheep nuclei. These data suggest that the nucleus contains the necessary signaling components for NO generation and provide further support of a functional intracellular RAS within the kidney.</jats:p></jats:sec>