Denervated and intact kidney responses to norepinephrine infusion in conscious dogs.

Effects of moderately hypertensive norepinephrine (NE) infusion on the function of denervated and innervated kidney were determined in conscious dogs chronically prepared by surgical splitting of the urinary bladder performed to enable separate urine collection from each kidney. While blood pressure increased 23 +/- 4 mm Hg and renal hemodynamics tended to increase slightly, sodium excretion of the denervated but not innervated kidney decreased significantly. This indicated a NE-stimulated increase in tubular sodium reabsorption. The effect was limited to the denervated kidney, possibly due to hypersensitivity of this organ's tubules to the circulating catecholamine. Previous blockade of alpha-receptors (phentolamine) appeared to blunt the dissociated response of the two kidneys to NE, whereas beta-receptor blockade (propranolol) did not affect it. This suggests that increasing sodium reabsorption of the denervated kidney depended on stimulation of tubular alpha-receptors. NE infusion impaired urine concentration equally in the intact and denervated kidney.