Excretory function after renal denervation and administration of diuretics to unanesthetized dogs

Abstract

Diuretics were administered intravenously to unanesthetized dogs with exteriorized ureters for separate urine collection from both kidneys: furosemide (0.2 mg/kg), ethacrynic acid (0.22 mg/kg), acetazolamide (3.0 mg/kg), amiloride (1.0 mg/kg b.w.). Diuresis, urine and plasma osmolality, excretion, clearances and excretion fractions of sodium, potassium, chloride and magnesium were determined. After left-side kidney denervation not later than 50 days after operation, the above mentioned diuretics were administered to the same animals. The responses of the denervated and intact kidneys were compared. During some of the experiments after furosemide administration isotonic solution of sodium chloride in a volume, adequate to the volume of the collected urine, was infused. Furosemide or ethacrynic acid administration leads to a higher increase of both diuresis and chloride excretion from denervated kidney as compared to the intact one. After ethacrynic acid administration magnesium excretion from the denervated kidney was registered to be higher than that from the intact one. After chronic renal denervation of unanesthetized dogs, chloride and magnesium reabsorption in the ascending limb of Henle's loop was greater in the denervated than in the intact kidney. Amiloride suppression of potassium secretion in the distal part of the nephron did not lead to differences between the denervated and intact kidneys. The decreased volume of extracellular liquid, resulting from diuretic action, did not change the response of the denervated kidney to furosemide or to ethacrynic acid.