Relations between sympathetic activation and plasma atrial natriuretic factor in man

To study the relationship between sympathetic activation and cardiac release of atrial natriuretic factor in man, plasma concentrations of norepinephrine, epinephrine and atrial natriuretic factor were measured in 20 patients before and after dynamic exercise (16 subjects) or the application of venous occlusion cuffs to the thighs (4 subjects). Plasma concentrations of norepinephrine, epinephrine and atrial natriuretic factor all increased during exercise, whereas venous occlusion produced a fall in plasma atrial natriuretic factor. There was no relation between basal plasma concentrations of atrial natriuretic factor and either norepinephrine or epinephrine. However, there was a linear relation between the changes in plasma atrial natriuretic factor induced by exercise or thigh cuffs and both plasma norepinephrine (r = 0.829, p less than 0.0001) and epinephrine (r = 0.733, p less than 0.001). We conclude that, in man, acute changes in sympathetic activity and release of atrial natriuretic factor are closely related. Further studies are required to determine whether this association is due wholly to the hemodynamic effects of sympathetic activation, or whether the latter has a direct effect on the release of atrial natriuretic factor.