The effects of renal denervation on the catecholamine concentrations in different areas of the central nervous system of the male Wistar rat were studied. Catecholamines were extracted following von Euler and Lishajko’s [1959] and Cohen and Goldenberg’s [1957] methods. Norepinephrine increased in the hypo thalami of denervated animals, 3, 7, and 30 days after the operation, compared to sham-operated animals. There were no modifications in the norepinephrine or epinephrine content in cerebral hemispheres, cerebellum, peduncles, pons and medulla oblongata, or in hypothalamic epinephrine after the same periods of time. Coincidentally, plasma renin activity decreased in denervated animals 7 days after the operation. The increase of endogenous norepinephrine found in hypothalamus might be attributed to the drop in plasma renin caused by renal denervation and a subsequent decrease in circulating angiotensin. This would be translated into a lower inhibition of neuronal re-uptake and a decrease in the neurotransmitter release.