THE BEHAVIOR OF RENAL BLOOD FLOW AFTER PARTIAL CONSTRICTION OF THE RENAL ARTERY

Abstract

Blood pressure in anaesthetized dogs was measured by Hamilton''s optical manometer, renal blood flow by thermostromuhrs placed on a renal artery. When a clamp placed on a renal artery distal to the stromuhr was tightened, producing partial arterial con striction, renal blood flow slowly returned toward the initial value. Subsequent tightenings of the clamp were followed by a tendency for this readjustment to take place. This is probably the result of internal renal yasodilatation, as it was accompanied by little or no change in blood pressure. Hypertension did not result from this ischemia in acute expts. When this vasodilator reflex was no longer active (at maximal vasodilatation) the reaction of the kidney to drugs was altered. Vaso-pressor drugs resulted in increase in flow.. Adrenalin, however, resulted in marked and prolonged renal vasoconstriction. Doses of the order of 0.05 [image] per kg gave this effect, the untreated kidney remaining unchanged. Prolonged hypertension of significant degree followed small doses in acute experiments in seven of eleven dogs; in three others slight hypertension resulted. Larger doses had none other than a transient effect when the renal artery was not constricted. The ischemic kidney was extremely susceptible to the vasoconstrictive action of adrenalin, and this vasoconstriction sometimes resulted in arterial hypertension.