The dopamine receptor antagonist haloperidol blocks natriuretic but not hypotensive effects of the atrial natriuretic factor.

Studies were performed on anesthetized male Münich-Wistar rats to investigate the influence of the dopamine (DA) receptor antagonist haloperidol on the natriuretic response to infusion of a synthetic atrial natriuretic factor. The whole kidney glomerular filtration rate (GFR), urinary excretion of electrolytes, and arterial blood pressure (BP) were therefore measured in groups of animals pretreated with haloperidol or vehicle and given a continuous intravenous infusion of atrial natriuretic peptide (ANP; 28 amino acids). Forty-five minutes of ANP infusion at 10 micrograms h-1 kg-1 body wt did not increase GFR (change from 1.14 +/- 0.08 to 1.15 +/- 0.05 ml min-1 g-1 kidney wt). Sodium excretion (UNaV) increased more than four-fold from 0.037 +/- 0.008 to 0.165 +/- 0.070 mumol min-1 g-1 kidney wt (P less than 0.01). Potassium excretion (UKV) increased by 86% (P less than 0.001) and the urine flow rate (V) increased transiently by 63% (P less than 0.05) and did not differ from the control value during the last 15 min of ANP infusion. The urinary sodium concentration (UNa) increased almost three-fold, while BP decreased by 14%. There was no change in urine osmolality. In animals pretreated with haloperidol (1 mg kg-1 body wt), 45 min of ANP infusion did not significantly alter GFR (from 1.10 +/- 0.08 to 0.98 +/- 0.09 ml min-1 g-1 kidney wt). The UNaV did not increase significantly (change from 0.026 +/- 0.006 to 0.030 +/- 0.009 mumol min-1 g-1 kidney wt). The UKV was not elevated by ANP infusion.(ABSTRACT TRUNCATED AT 250 WORDS)