ROLE OF CARDIAC INNERVATION IN ATRIAL-NATRIURETIC-PEPTIDE SECRETION IN TRANSPLANTED HEART RECIPIENTS

To investigate whether cardiac innervation modulates atrial natriureti c peptide (ANP) secretion, we performed acute volume expansion on eigh t normal and eight matched (age, weight, and total blood volume) trans planted denervated heart patients (Htx), while monitoring fluid-regula ting hormone, systemic blood pressure, and echocardiographic atrial ar ea changes. At rest, plasma ANP and guanosine 3',5'-cyclic monophospha te (cGMP) were lower in control subjects than in Htx (45 +/- 16 vs. 10 3 +/- 35 pg/l and 0.9 +/- 0.3 vs. 3.5 +/- 1.4 pM, respectively; P < 0. 001). Plasma active renin, aldosterone, and catecholamines did not dif fer significantly in the two populations, whereas arginine vasopressin and cortisol were higher in controls (P < 0.01 and P < 0.005). Althou gh volume expansion (+15%) and atrial stretch were similar in the two groups, plasma ANP and cGMP increased significantly only in the Htx gr oup (103 +/- 35 to 189 +/- 69 pg/l and 3.5 +/- 1.4 to 5.8 +/- 1.4 pM, respectively; P < 0.001). The decrease observed for the other hormones was not significant except for arginine vasopressin and cortisol (P < 0.05 and P < 0.001) in the control group. These results support the h ypothesis of an inhibitory role of cardiac innervation in biologically active ANP secretion in humans, at rest and after acute volume expans ion.