Lack of neural control of atrial natriuretic peptide release in conscious dogs

To determine whether or not cardiac nerves control the release of atrial natriuretic polypeptide (ANP), we examined the effects of intrapericardial cardiac denervation on circulating ANP in conscious dogs. Base-line level of circulating ANP in six cardiac-denervated (CD) dogs (191 +/- 24 pg/ml) was not significantly different from that in seven intact (INT) dogs (196 +/- 18 pg/ml). Three percent dextran-40 in saline (18 ml/kg, 20% of estimated blood volume) was infused over 5 min, and the elevated left atrial pressure (LAP; approximately 8 mmHg) was maintained by supplemental infusion over 40 min. The increase in circulating ANP after infusion in the CD dogs (462 +/- 61 pg/ml) was not significantly different from that in the INT dogs (435 +/- 73 pg/ml). The regression line relating circulating ANP (normalized with regard to the control value) with the change in LAP in the INT dogs was not significantly different from that in the CD dogs. These results suggest that the cardiac nerves do not control the tonic release of ANP or the volume expansion-induced release of ANP.