Does infusion of ANG II increase muscle sympathetic nerve activity in patients with primary aldosteronism?

Am J Physiol Regul Integr Comp Physiol. 2008 Jun;294(6):R1873-9. doi: 10.1152/ajpregu.00471.2007. Epub 2008 Mar 26.


Patients with primary aldosteronism (PA) were shown to have suppressed muscle sympathetic nerve activity (MSNA) in our previous study. Although baroreflex inhibition probably accounts in part for this reduced MSNA in PA, we hypothesized that the lowered activity of the renin-angiotensin system in PA may also contribute to the suppressed SNA. We recorded MSNA in 9 PA and 16 age-matched normotensive controls (NC). In PA, the resting mean blood pressure (MBP) and serum sodium concentrations were increased, and MSNA was reduced. We examined the effects of infusion of a high physiological dose of ANG II (5.0 on MSNA in 6 of 9 PA and 9 of 16 NC. Infusion of ANG II caused a greater pressor response in PA than NC, but, in spite of the greater increase in pressure, MSNA increased in PA, whereas it decreased in NC. Simultaneous infusion of nitroprusside and ANG II, to maintain central venous pressure at the baseline level and reduce the elevation in MBP induced by ANG II, caused significantly greater increases in MSNA in PA than in NC. Baroreflex sensitivity of heart rate, estimated during phenylephrine infusions, was reduced in PA, but baroreflex sensitivity of MSNA was unchanged in PA compared with NC. All the abnormalities in PA were eliminated following unilateral adrenalectomy. In conclusion, the suppressed SNA in PA depends in part on the low level of ANG II in these patients.

Publication types

  • Controlled Clinical Trial

MeSH terms

  • Adrenalectomy
  • Adult
  • Aldosterone / blood
  • Angiotensin II / pharmacology*
  • Baroreflex / drug effects
  • Baroreflex / physiology
  • Blood Pressure / drug effects
  • Blood Pressure / physiology
  • Dose-Response Relationship, Drug
  • Female
  • Heart Rate / drug effects
  • Heart Rate / physiology
  • Humans
  • Hyperaldosteronism / physiopathology*
  • Male
  • Middle Aged
  • Muscle, Skeletal / drug effects
  • Muscle, Skeletal / innervation*
  • Nitroprusside / pharmacology
  • Phenylephrine / pharmacology
  • Renin / blood
  • Renin-Angiotensin System / drug effects
  • Renin-Angiotensin System / physiology
  • Sodium / blood
  • Sympathetic Nervous System / drug effects*
  • Sympathetic Nervous System / physiology
  • Sympathomimetics / pharmacology


  • Sympathomimetics
  • Angiotensin II
  • Nitroprusside
  • Phenylephrine
  • Aldosterone
  • Sodium
  • Renin