Nitric oxide-dependent vasodilation in young spontaneously hypertensive rats

Alberto Radaelli, Luca Mircoli, Ileana Mori, Giuseppe Mancia, Alberto U. Ferrari

Research output: Contribution to journalArticlepeer-review


Conflicting evidence exists on the possible impairment of tonic nitric oxide (NO)-mediated vasodilation as a causative factor in the genesis of human as well as experimental hypertension. We evaluated the tonic NO- dependent vasodilation from the pressor response to NO synthesis inhibition by N(G)-monomethyl-L-arginine (L-NMMA) in 9 conscious, chronically instrumented spontaneously hypertensive rats (SHR) at 12 weeks of age, ie, during the early established hypertensive stage. Nine age-matched Wistar- Kyoto rats (WKY) were used as controls. The pressor responses to L-NMMA (100 mg · kg-1 IV bolus plus 1.5 mg · kg-1 · min-1 infusion for 60 minutes) as well as to non-NO-dependent pressor stimuli, namely, vasopressin (2, 4, and 8 ng · kg-1) and phenylephrine (0.5, 1, and 2 μg · kg-1) given as IV boluses, were assessed both under control conditions and during suppression of autonomic reflexes by hexamethonium (30 mg · kg-1 IV bolus+1.5 mg · kg-1 · min-1 infusion). Rather than being reduced, the pressor responses to L-NMMA were 39% and 71% larger in the control and areflexic conditions, respectively, than those observed in WKY (both P

Original languageEnglish
Pages (from-to)735-739
Number of pages5
Issue number4
Publication statusPublished - Oct 1998


  • Hexamethonium
  • L-NAME
  • Nitric oxide
  • Rats, inbred SHR
  • Vascular reactivity

ASJC Scopus subject areas

  • Internal Medicine


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