Is the secretion of atrial natriuretic peptide in man under neural control?

Aims Previous work has described short-term variation in the circulating pl asma level of atrial natriuretic peptide (ANP), but the mechanism remains u nknown. Our aim was to investigate the role of cardiac innervation in this variability. Methods and Results Blood samples were obtained from the right atrium via a pulmonary artery flotation catheter every 2 min over a 90 min period. Seve n patients who underwent cardiac transplantation by the standard biatrial t echnique (partial innervation) and ten patients who underwent transplantati on by the bicaval technique (total denervation) were studied. ANP levels we re measured by radioimmunoassay. The median ANP levels were somewhat higher in the biatrial group compared to the bicaval group [470 (150-1095) vs 216 (100-605) pg.ml(-1); median (range); P=ns], and both were much higher than normal levels in the pulmonary artery (40 (24, 56) pg ml(-1); median and i nterquartile range). In both transplant groups circulating plasma ANP level s showed considerable variability. The median number of 'peaks' and 'trough s', as counted by visual inspection, were not significantly different betwe en the two groups. Computer analysis identified 12-16 and 6-15 'pulses' in the biatrial and bicaval group, respectively. Further analysis revealed tha t pulse amplitude, height and area were significantly higher in the biatria l compared to the bicaval group. Conclusion It would appear that variability of circulating plasma levels of ANP is preserved despite complete or partial cardiac denervation, and so a neural mechanism does not appear to account for such variation. (C) 2000 T he European Society of Cardiology.