Baroreceptor denervation prevents sympathoinhibition during angiotensin II-induced hypertension

Hypertension. 2005 Jul;46(1):168-72. doi: 10.1161/01.HYP.0000168047.09637.d4. Epub 2005 May 23.

Abstract

Arterial baroreflexes are well established to provide the basis for short-term control of arterial pressure; however, their role in long-term pressure control is more controversial. We proposed that if the sustained decrease in renal sympathetic nerve activity (RSNA) we observed previously in response to angiotensin II-induced hypertension is baroreflex mediated, then the decrease in RSNA in response to angiotensin II would not occur in sinoaortic-denervated (SAD) animals. Arterial pressure and RSNA were recorded continuously via telemetry in sham and SAD rabbits living in their home cages before, during, and after a 7-day infusion of angiotensin II (50 ng . kg(-1) . min(-1)). The arterial pressure responses in the 2 groups of rabbits were not significantly different (82+/-3 mm Hg sham versus 83+/-3 mm Hg SAD before angiotensin II infusion, and 101+/-6 mm Hg sham versus 100+/-4 mm Hg SAD day 6 of angiotensin II). In sham rabbits, there was a significant sustained decrease in RSNA (53+/-7% of baseline on day 2 and 65+/-7% on day 6 of the angiotensin II). On ceasing the angiotensin II, all variables recovered to baseline. In contrast, RSNA did not change in SAD rabbits with the angiotensin II infusion (RSNA was 98+/-8% of baseline on day 2 and 98+/-8% on day 6 of the angiotensin II infusion). These results support our hypothesis that the reduction in RSNA in response to a pressor dose of angiotensin II is dependent on an intact arterial baroreflex pathway.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Angiotensin II / pharmacology*
  • Animals
  • Denervation*
  • Hypertension / chemically induced
  • Hypertension / physiopathology*
  • Kidney / innervation
  • Neural Inhibition* / drug effects
  • Pressoreceptors / physiopathology*
  • Rabbits
  • Sinoatrial Node / innervation
  • Sinus of Valsalva / innervation
  • Sympathetic Nervous System / drug effects
  • Sympathetic Nervous System / physiopathology*
  • Vasoconstrictor Agents / pharmacology

Substances

  • Vasoconstrictor Agents
  • Angiotensin II