Effect of nitric oxide synthase inhibitor on diaphragmatic function after resistive loading

Teresa Bisnett, Antonio Anzueto, Francisco H. Andrade, George G. Rodney, William R. Napier, Stephanie M. Levine, Leo C. Maxwell, Patient Mureeba, Stephen D. Derdak, Matthew B. Grisham, Stephen G. Jenkinson

Research output: Contribution to journalReview articlepeer-review

10 Scopus citations

Abstract

We studied the effect of a nitric oxide synthase inhibitor, N(ω)- Nitro-L-arginine-methyl-ester (L-NAME), on in vitro diaphragmatic function both at rest (control) or after inspiratory resistive loading (IRL). Sprague- Dawley rats were anesthetized, instrumented, and then the following experimental groups: (1) controls; (2) L-NAME (100 mg/kg/body weight intravenously alone); (3) IRL alone; and (4) L-NAME + IRL. The IRL protocol consisted of applying a variable resistor to the inspiratory limb of a two- way valve at 70% of maximal airway pressure until apnea. After the experiment, the animals were sacrificed and diaphragmatic strips were obtained for activity of constitutive nitric oxide synthase (cNOS) and measurements of in vitro contractile properties: tetanic (Po) and twitch tensions (Pt). cNOS activity was significantly decreased in the L-NAME and L- NAME + IRL groups (P ≤ 0.05) as compared with control and IRL groups. L- NAME alone did not affect Pc or Pt. However, in both IRL groups, with and without was a significant decrease in Pc and Pt. This reduction was comparable in both groups. In summary, our data showed that L-NAME resulted in a significant decrease cNOS activity, but in vitro contractility was impaired.

Original languageEnglish (US)
Pages (from-to)185-190
Number of pages6
JournalComparative Biochemistry and Physiology - A Molecular and Integrative Physiology
Volume119
Issue number1
DOIs
StatePublished - Jan 1 1998

Keywords

  • Diaphragmatic fatigue
  • N(ω)-Nitro-L-arginine-methyl-ester
  • Nitric oxide
  • Resistive loading

ASJC Scopus subject areas

  • Biochemistry
  • Physiology
  • Molecular Biology

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