Heart atrial auriectomy reduces the diuretic and natriuretic responses to a hypertonic saline load

Acute bilateral atrial auriectomy in anesthetized dogs reduced diuresis and natriuresis induced by both extracellular fluid volume expansion with isotonic saline and a hypertonic saline load. Since a hypertonic saline load, in contrast to isotonic saline infusion, was not accompanied by a significant increase in central venous pressure it is proposed that either increased plasma osmolality or plasma sodium concentration (or both) participate in the modulation of the atrial natriuretic mechanism.