Evidence against the central nervous system involved in altered reflex control of sympathetic nerve activity by atrial natriuretic peptide

This study aimed to examine whether atrial natriuretic peptide (ANP) alters arterial baroreceptor control of sympathetic nerve activity (SNA) by acting on the central nervous system (CNS). In rabbits anesthetized with αchloralose, we examined changes in arterial pressure and renal SNA in response to graded electrical stimulation (1.7, 3.3, 5.0 Hz) of aortic depressor nerves during the intravenous (IV) infusion of saline or αhuman atrial natriuretic peptide (αhANP) (0.1, 1.0 μg/kg/min) or after the intracerebroventricular (ICV) injections of saline or αhANP (3, 10 μg). Sinoaortic denervation and bilateral vagotomy were done before examination in all rabbits to eliminate the influence of the known effects of ANP on arterial and cardiac receptors. IV αhANP decreased arterial pressure but did not alter renal SNA. ICV αhANP did not change arterial pressure or renal SNA. Arterial pressure and renal nerve responses to graded electrical stimulation of aortic depressor nerves were not altered by IV or ICV αhANP. These results suggest that αhANP does not modulate control of renal SNA by acting on CNS.