The influence of beta-adrenoceptive receptor blocking agents on urinary function in the rat

Abstract

1. Intramuscular or subcutaneous injections of isoprenaline and dichloroisoprenaline and subcutaneous injection of pronethalol reduced the rates of excretion of water, sodium, potassium and chloride in the urine of conscious, hydrated rats. Inulin excretion usually fell at high, but not at low, dose levels. These changes were attributed to direct stimulant actions on beta-adrenoceptors in the kidney.2. A reduction in perfusion pressure to the kidney may also have contributed to these urinary changes, because isoprenaline produced a transient fall in mean arterial blood pressure when given subcutaneously to anaesthetized rats.3. Intramuscular injection of pronethalol and subcutaneous injection of antidiuretic hormone both reduced the rate of urine flow without modifying other parameters of urinary function (excretion of inulin and electrolytes were not diminished).4. This latter action of pronethalol could not be ascribed to an increased secretion of antidiuretic hormone, for it also occurred in hypophysectomized rats.5. Propranolol increased the renal excretion of sodium and chloride. A small rise in urinary potassium levels also occurred but urine volume and inulin excretion were not modified. Some possible modes of action of propranolol are discussed.