Importance of the sympathetic nervous system in the development of renal hypertension in the rat.

1. Chemical sympathectomy with 6-hydroxydopamine (6-OHDA) prevented the development of renal hypertension in 80% of weanling male rats of the C.F. strain.2. Adult male rats treated with 6-OHDA developed hypertension on bilateral clamping of the renal arteries.3. Demedullation of the adrenal glands followed by 6-OHDA treatment in adult rats prevented the development of hypertension in 75% of them.4. Weanling rats treated with 6-OHDA did not have any measurable catecholamines in their hearts up to 72-78 days after treatment.5. Unlike the weanling rats, the hearts of adult rats (demedullated or with intact medulla) showed significant refilling (40-50%) of catecholamine stores 60 days after 6-OHDA treatment.6. It is concluded that the functional sympathetic nervous system is important in the development of renal hypertension in the rat.