Diuresis in Rats: Effects of Sympathomimetic and Sympathetic Blocking Agents

Abstract

Dopamine and tyramine possess diuretic properties resembling but weaker than those of noradrenaline in the rat. These three amines produce a relatively smaller loss of sodium than does adrenaline. Bretylium shows a diuretic action which is apparently associated with its sympathomimetic properties and which is antagonized by phenoxybenzamine. However, bretylium causes a relatively greater loss of potassium and chloride than do the sympathomimetic amines. A slight antidiuretic action is shown by bretylium after its diuretic effect has subsided and a similar effect is produced by BW 172C58, which has relatively weak sympathomimetic properties. In contrast to these adrenergic neurone blocking agents, phenoxybenzamine and a ganglion blocking agent (pentacynium) show powerful antidiuretic effects. These observations are consistent with the view that the adrenal medulla has an important role in facilitating water diuresis in rats.

Metabolic Studies in a Patient With a Phaeochromocytoma Associated With Hypokalaemia and Hyperaldosteronism

“…With more long-term infusion in man, Laragh (1962), Tuttle (1962) and Ames et al (1965) showed that noradrenaline induced a small natriuresis and that this effect was more marked in sodium-depleted subjects. Green & Sim (1961) demonstrated that both adrenaline and noradrenaline could induce natriuresis in rats, and that pretreatment with phenoxybenzamine greatly reduced the diuretic effect. Pearson & Williams (1968) showed in dogs that noradrenaline administered into the left renal artery had a direct sodium-retaining effect on the kidney, and that the natriuresis induced by systemic administration of noradrenaline seemed to depend upon increased systemic arterial blood pressure and a concentration with minimal direct renal actions.…”

Renal tubular flow dynamics during angiotensin diuresis in the rat

“…Both noradrenaline and adrenaline are known to be capable of producing diuretic responses in conscious rats (Dexter & Stoner, 1952;Green & Sim, 1961). When infused in equipressor amounts into cirrhotic subjects, angiotensin caused a considerably greater degree of natriuresis than noradrenaline (Laragh, Cannon, Bentzel, Sicinski & Meltzer, 1963).…”