Abstract
In order to investigate the peripheral neuroeffector functions of renal hypertension, norepinephrine release from the sympathetic nerve endings and vascular responsiveness were evaluated in the mesenteric vasculatures from two-kidney, one-clip Goldblatt hypertensive rats (2K, 1G-HT). Norepinephrine release and pressor responses during periarterial nerve stimulation (40V, 5msec rectangular pulses for 1min, 5, 10 and 15Hz) were unchanged during the acute phase (3 weeks after surgery), and were rather reduced during the chronic phase (7-8 weeks after surgery) in 2K, 1G-HT compared to sham-operated normotensive control rats. By contrast, the vasoconstrictor responses to exogenously applied norepinephrine were significantly greater in 2K, 1G-HT than in the normotensive controls. From these observations, it seems unlikely that peripheral adrenergic function in the blood vessels plays an important role in the pathogenesis of 2K, 1G-HT. However, the increased sensitivity of vascular smooth muscle cells to norepinephrine may contribute to the maintenance of high blood pressure in the face of reduced vascular sympathetic tone in this form of hypertension
