In rats, atrial natriuretic peptide secretion is regulated differently in the right and left atria

Recent studies have suggested the secretion of Atrial Natriuretic Peptide (ANP) is regulated by receptor mediated activation of protein kinase C, which causes the autocrine release of prostaglandins. Prostaglandins stimulate ANP secretion via the adenylate cyclase second messenger system. This report examined the response of right and left atrial ANP secreting cells to the three endothelin isopeptides and to cyclooxygenase inhibition. Our results show that right atrial ANP secretion is stimulated by endothelin 1 and 2 but not 3. In addition, right atrial ANP secretion is reduced by inhibition of cyclooxygenase. In contrast, left atrial ANP secretion is stimulated by endothelin 2 and 3 but not 1. Inhibition of cyclooxygenase did not affect left atrial ANP secretion. These results show the regulation of ANP secretion is different between the two atrial chambers. Right atrial cells appear to contain the prostaglandin-mediated response to protein-kinase C activation, whereas left atrial cells regulate ANP secretion differently.