The present study was conducted to investigate the possible role of the sympathetic nervous system in two-kidney, one clip (2K1C) and deoxycorticosterone acetate (DOCA)-salt hypertension. 2K1C and DOCA-salt hypertension were made in Sprague-Dawley rats. Four weeks after induction of hypertension, systolic blood pressure measured in conscious state was significantly higher in 2K1C (216+/-18 mmHg) and DOCA-salt (205+/-29 mmHg) groups than that in control (128+/-4 mmHg). The third branches (<300 micrometer in outer diameter) of the mesenteric artery were isolated and cut into ring segments of 2apprx3 mm in length. Each ring segment was mounted in tissue bath and connected to a force displacement transducer for measurement of isometric tension. The arterial rings were contracted by application of norepinephrine (NE) in a dose-dependent manner. The amplitude of the NE-induced contraction of the vessels was significantly larger in hypertension than in control. The NE-induced contraction was significantly enhanced by neuropeptide Y (NPY) in hypertension. Reciprocally, NPY-elicited vasocontraction was increased by NE in hypertension. These results suggest that the sympathetic nervous system contributes to the development of 2K1C and DOCA-salt hypertension.
Animals ; Baths ; Blood Pressure ; Desoxycorticosterone ; Hypertension ; Mesenteric Arteries* ; Neuropeptide Y* ; Neuropeptides* ; Norepinephrine* ; Rats* ; Rats, Sprague-Dawley ; Sympathetic Nervous System ; Transducers

The present study was aimed at investigating whether the development of hypertension is related with an altered expression of nitric oxide synthases (NOS) in the kidney. By Western blot analysis, the expression of bNOS and ecNOS isoforms was determined in the kidney of deoxycorticosterone acetate (DOCA)-salt and two-kidney, one clip (2K1C) rats. In DOCA-salt hypertension, the expression of both bNOS and ecNOS was decreased, along with tissue contents of nitrites. In 2K1C hypertension, the nitrite content of the clipped kidney was decreased along with ecNOS levels, whereas neither the nitrite content nor the expression of NOS isoforms was significantly altered in the contralateral non-clipped kidney. These results suggest that the development of hypertension is associated with an altered renal expression of NOS and nitric oxide generation in DOCA-salt and 2K1C rats.
Animals ; Blotting, Western ; Desoxycorticosterone ; Hypertension ; Kidney ; Nitric Oxide* ; Nitrites ; Protein Isoforms ; Rats*