Role of renal nerves in development of hypertension in DOCA-salt model in rats: a telemetric approach

Am J Physiol Heart Circ Physiol. 2005 Oct;289(4):H1519-29. doi: 10.1152/ajpheart.00206.2005. Epub 2005 Jun 3.

Abstract

Centrally mediated hyperactivity of the autonomic nervous system contributes to DOCA hypertension; however, the targeted peripheral vascular bed(s) remain unclear. We propose that if renal sympathetic activity is a factor in the development of DOCA-salt hypertension, then renal denervation (RDNX) should attenuate the hypertensive response. In protocol 1, uninephrectomized RDNX (n = 9) and sham-denervated (n = 6) Sprague-Dawley rats were allowed free access to 0.9% NaCl solution and 0.1% NaCl diet. Mean arterial pressure (MAP) and heart rate were telemetrically recorded for 4 days before and 36 days after DOCA (100 mg/rat) implantation; sodium and water balances were recorded daily. Protocol 2 was similar except that saline intake in sham rats (n = 7) was matched to that observed in RDNX rats of protocol 1 for 30 days; for the last 10 days, the rats were allowed free access to saline. Before DOCA in protocol 1, MAP was lower (P < 0.05) in RDNX rats (99 +/- 1 mmHg) compared with sham rats (111 +/- 3 mmHg); however, heart rate and sodium and water balances were similar between groups. RDNX attenuated the MAP response to DOCA by approximately 50% (DeltaMAP = 22 +/- 3 mmHg, where Delta is change in MAP) when compared with sham rats (DeltaMAP = 38 +/- 6). RDNX rats consumed significantly less saline than sham rats, and cumulative sodium and water balances were reduced by 33% and 23%, respectively. In protocol 2, a similar pattern in MAP elevation was observed in RDNX and saline-restricted, sham-denervated rats even when saline restriction was removed. These results indicate that the renal sympathetic nerves are important in hypertension development but that other factors are also involved.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Blood Pressure
  • Body Weight
  • Desoxycorticosterone
  • Disease Models, Animal
  • Heart Rate
  • Hypertension, Renal / chemically induced
  • Hypertension, Renal / physiopathology*
  • Kidney / blood supply
  • Kidney / innervation*
  • Kidney / physiopathology
  • Male
  • Rats
  • Rats, Sprague-Dawley
  • Renal Circulation / physiology*
  • Sodium Chloride
  • Sympathectomy
  • Sympathetic Nervous System / physiopathology*
  • Telemetry
  • Water-Electrolyte Balance / physiology

Substances

  • Desoxycorticosterone
  • Sodium Chloride