Evidence against the central nervous system being 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 CNS. In rabbits anesthetized with alpha-chloralose, 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 i.v. infusion of saline or alpha-human atrial natriuretic peptide (alpha-hANP) (0.1, 1.0 microgram/kg/min) or after the i.c.v. injections of saline or alpha-hANP (3, 10 micrograms). 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. I.v. alpha-hANP decreased arterial pressure but did not alter renal SNA. I.c.v. alpha-hANP 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 i.v. or i.c.v. alpha-hANP. These results suggest that alpha-hANP does not modulate control of renal SNA by acting on the CNS.