[Effects of alpha and beta receptor blockaders on urinary excretion of sodium and potassium in healthy rats and in those with chronic renal failure]

Abstract

The aim the study was to investigate the effects of both alpha and beta adrenergic blockade on sodium and potassium excretion in rats with chronic renal failure. The chronic renal failure was induced by surgical ablation of 75% renal mass. Controls were shame operated rats. All experiments were performed under sodium pentobarbitone anesthesia. Blood pressure was measured intraarterially and glomerular filtration rate was estimated as inulin clearance. Phentolamine (4 micrograms/kg/min)--Group I; or propranolol (4 micrograms/kg/min)--Group II were infused i.v. to controls and chronic failure rats. alpha-receptor blockade with phentolamine lowered GFR and blood pressure to the same extent in controls and rats with chronic renal failure. alpha-blockade caused increased fractional sodium excretion only in controls while urinary excretion of sodium and potassium fell in rats with chronic renal failure. The beta-blockade with propranolol (4 micrograms/kg/min)--Group II did not affect both blood pressure and GFR either in controls nor in rats with chronic renal failure. However propranolol infusion increased sodium and potassium excretion in controls but not in rats with chronic renal failure. Our study showed the divergence in the role of adrenergic receptors in regulation of urinary electrolytes excretion between controls and rats with chronic renal failure.