Sympathetic activation in rats with L-NAME-induced hypertension

Vinicia Campana Biancardi, C. T. Bergamaschi, O. U. Lopes, R. R. Campos

Research output: Contribution to journalArticle

35 Citations (Scopus)

Abstract

We evaluated the hemodynamic pattern and the contribution of the sympathetic nervous system in conscious and anesthetized (1.4 g/kg urethane, iv) Wistar rats with L-NAME-induced hypertension (20 mg/kg daily). The basal hemodynamic profile was similar for hypertensive animals, conscious (N = 12) or anesthetized (N = 12) treated with L-NAME for 2 or 7 days: increase of total peripheral resistance associated with a decrease of cardiac output (CO) compared to normotensive animals, conscious (N = 14) or anesthetized (N = 14). Sympathetic blockade with hexamethonium essentially caused a decrease in total peripheral resistance in hypertensive animals (conscious, 2 days: from (means ± SEM) 2.47 ± 0.08 to 2.14 ± 0.07; conscious, 7 days: from 2.85 ± 0.13 to 2.07 ± 0.33; anesthetized, 2 days: from 3.00 ± 0.09 to 1.83 ± 0.25 and anesthetized, 7 days: from 3.56 ± 0.11 to 1.53 ± 0.10 mmHg mL-1 min-1) with no change in CO in either group. However, in the normotensive group a fall in CO (conscious: from 125 ± 4.5 to 96 ± 4; anesthetized: from 118 ± 1.5 to 104 ± 5.5 mL /min) was observed. The responses after hexamethonium were more prominent in the hypertensive anesthetized group. However, no difference was observed between conscious and anesthetized normotensive rats in response to sympathetic blockade. The present study shows that the vasoconstriction in response to L-NAME was mediated by the sympathetic drive. The sympathetic tone plays an important role in the initiation and maintenance of hypertension.

Original languageEnglish (US)
Pages (from-to)401-408
Number of pages8
JournalBrazilian Journal of Medical and Biological Research
Volume40
Issue number3
DOIs
StatePublished - Jan 1 2007

Fingerprint

NG-Nitroarginine Methyl Ester
Cardiac Output
Rats
Hexamethonium
Animals
Chemical activation
Hemodynamics
Hypertension
Vascular Resistance
Urethane
Sympathetic Nervous System
Neurology
Vasoconstriction
Wistar Rats
Maintenance
Scanning electron microscopy

Keywords

  • L-NAME hypertension
  • Nitric oxide synthase blockade
  • Sympathetic nervous system
  • Total peripheral resistance

ASJC Scopus subject areas

  • Biophysics
  • Neuroscience(all)
  • Biochemistry
  • Physiology
  • Immunology
  • Pharmacology, Toxicology and Pharmaceutics(all)
  • Cell Biology

Cite this

Sympathetic activation in rats with L-NAME-induced hypertension. / Biancardi, Vinicia Campana; Bergamaschi, C. T.; Lopes, O. U.; Campos, R. R.

In: Brazilian Journal of Medical and Biological Research, Vol. 40, No. 3, 01.01.2007, p. 401-408.

Research output: Contribution to journalArticle

Biancardi, Vinicia Campana ; Bergamaschi, C. T. ; Lopes, O. U. ; Campos, R. R. / Sympathetic activation in rats with L-NAME-induced hypertension. In: Brazilian Journal of Medical and Biological Research. 2007 ; Vol. 40, No. 3. pp. 401-408.
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