Changes in NOS activity and protein expression during acute and prolonged ANG II administration

1 Department of Physiology, University of Murcia School of Medicine, E-30100 Murcia; 2 Fundación Jiménez Díaz, E-28040 Madrid; and 3 Department of Medical Sciences, University of Castilla-La Mancha, E-02071 Albacete, Spain The aim of this study was to assess the effects of acute or prolonged increases of ANG II on nitric oxide synthase (NOS) activities and protein expression in mesenteric resistance vessels, left ventricle, renal cortex, and renal medulla. The response of NOS activities to ANG II is compared with that induced by phenylephrine. ANG II or phenylephrine were infused over either 3 h or 3 days to conscious rats. NOS activity was examined by measuring the rate of conversion of L -[ 14 C]arginine to L -[ 14 C]citrulline. Protein levels of endothelial (e) and neuronal (n) NOS were determined by Western blot analysis. Arterial pressure (AP) increased ( P