EFFECTS OF ADENOSINE INFUSION ON RENAL-FUNCTION, PLASMA ANP AND ADH CONCENTRATIONS AND CENTRAL HEMODYNAMICS IN ANESTHETIZED PIGS

1. The effect of high dose adenosine administration on atrial natriure tic peptide (ANP) and antidiuretic hormone (ADH) release is not comple tely understood, and data concerning the effect of adenosine on renal and systemic hemodynamics in the pig are lacking. Measurements of cent ral hemodynamics, renal blood flow and urine production were made in a nesthetized pigs during infusion of adenosine. The relationship betwee n these parameters and the plasma concentrations of ANP, ADH and renal renin production was examined. 2. Adenosine infusion at the rate of 1 40 mg/kg per minute resulted in a significant decrease in systolic, di astolic and mean arterial blood pressure as well as pulmonary arterial pressure. However, cardiac output and renal blood flow remained uncha nged during adenosine infusion. Likewise, heart rate remained unchange d until the end of infusion when it increased significantly. Plasma AN P and ADH concentrations increased significantly within 30 min after a denosine infusion, reaching peak levels at 30 to 60 min, However, desp ite the significant decrease in arterial blood pressure, renal renin p roduction did not change significantly. 3. The adenosine-induced rise in ANP, which is normally released by atrial stretch, may represent a direct effect of adenosine on the cardiac myocytes. The increase in AD H may be a result of decreased arterial blood pressure triggering stim ulatory signals from the aortic arch and carotid body receptors to hyp othalamic-pituitary sites of ADH production/release. Urine flow decrea sed dramatically within 30 min of adenosine infusion. Thus adenosine i nfusion at the given rate led to marked reduction in systemic and pulm onary arterial pressures without significant change in cardiac output, heart rate and renal blood flow. This was associated with a marked in crease in plasma ANP and ADH levels with no significant change in rena l renin production despite a marked reduction in arterial blood pressu re. 4. Maintenance of renal blood flow despite marked reduction in per fusion pressure suggests that, at high doses, adenosine induces renal vasodilation in pigs as opposed to a combined afferent and efferent va soconstriction known to occur under different experimental conditions. Copyright (C) 1997 Elsevier Science Inc.