Role of Angiotensin II and Nitric Oxide in the Rat Paraventricular Nucleus

Role of Angiotensin II and Nitric Oxide in the Rat Paraventricular Nucleus

<P> To investigate the mutual relationship between angiotensin II (Ang II) and nitric oxide (NO) in paraventricular nucleus (PVN), Ang II receptor type Ia (AT<SUB>1A</SUB>), type Ib (AT<SUB>1B</SUB>), endothelial constitutive nitric oxide synthase (ecNOS), and neuronal constitutive nitric oxide synthase (ncNOS) mRNA levels of rat PVN were measured after unilateral carotid artery ligation. AT<SUB>1A</SUB> and AT<SUB>1B</SUB> mRNA levels were markedly elevated 6 hrs after unilateral carotid artery ligation. Losartan injection (10μg/0.3μl) into the PVN augmented of the increment of AT<SUB>1A</SUB> and AT<SUB>1B</SUB> mRNAs It also increased ecNOS gene expression. In addition, AT<SUB>1B</SUB> mRNA levels increased after N-nitro-L-arginine methyl ester (L-NAME) injection (50μg/0.3μl) into the PVN. These results suggest that Ang II and NO in the rat PVN may interplay, at least in part, through regulation of gene expression of ecNOS and AT<SUB>1B</SUB>, respectively.