Development and maintenance of renal hypertension in normal and guanethidine sympathectomized rats

The sympathetic nervous system has been postulated to play a role in the maintenance of renal hypertension. Permanent peripheral sympathectomy was performed by treating newborn rats for 21 days with guanethidine. Sympathectomy was confirmed by (1) relative insensitivity to tyramine, (2) lack of responsiveness to renal nerve stimulation, and (3) absence of dopamine-beta-hydroxylase immunofluorescence in renal blood vessels. Placement of a clip on the left renal artery led to the development of two-kidney renal hypertension. No differences were observed between the two-kidney renal hypertensive normal and sympathectomized rats; both had elevated plasma renin activity and vasodepression with angiotensin antagonists which were maintained up to nine weeks. Furthermore, in normal rats chronic beta-adrenergic blockade with propranolol caused no change in the development of the two-kidney renal hypertension. Similarly, no differences were seen in blood pressure, plasma renin activity, or response to antagonists between the one-kidney renal hypertensive (clip plus contralateral nephrectomy) normal and sympathectomized rats. Both showed sustained low renin hypertension up to 12 weeks. The absence of the peripheral sympathetic nervous system did not affect the development or maintenance of hypertension in either model of hypertension.