RESUMO
The importance of the hemodynamic parameters in the hypertensive rats by subtotal nephrectomy and the role of the neurogenic tone in the maintenance of high blood pressure were studied. The baroreceptor sensitivity is significantly diminished in the hypertensive rats with respect to normal ones. The resistance of the hindquarters to perfusion with constant flows was decreased in the hypertensive animals. No differences were observed in the arterial pressure, cardiac output, heart rate, stroke volume and peripheral resistance between both groups of anesthetized animals. The pressure response to the phenylephrine injection was higher in the conscious hypertensive animals than in the normotensive rats but it was the same after the anesthesia and the blocking of ganglionic transmission. These results suggest that an increment of the neurogenic tone exists in the chronic phase of hypertension in this experimental model and it could be responsible for the elevated blood pressure.
