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Analytical Techniques for Assaying Nitric Oxide Bioactivity
11:28

Analytical Techniques for Assaying Nitric Oxide Bioactivity

Published on: June 18, 2012

Nitric oxide inhibits the positive inotropic response to beta-adrenergic stimulation in humans with left ventricular

J M Hare1, E Loh, M A Creager

  • 1Cardiomyopathy Center, Boston University School of Medicine, MA 02118, USA.

Circulation
|October 15, 1995
PubMed

Insights

Nitric oxide (NO) in the heart reduces the response to beta-adrenergic stimulation in patients with left ventricular (LV) dysfunction. Inhibiting NO enhances this response, suggesting NO contributes to hyporesponsiveness.

Area of Science:

  • Cardiology
  • Physiology
  • Pharmacology

Background:

  • Nitric oxide (NO) is known to reduce cardiac contractility in response to beta-adrenergic stimulation.
  • This effect has been observed in cell cultures and animal models.

Purpose of the Study:

  • To investigate if endogenously produced nitric oxide (NO) in the human heart inhibits the positive inotropic effects of beta-adrenergic stimulation.
  • To test this in patients with left ventricular (LV) dysfunction.

Main Methods:

  • Patients with LV dysfunction received dobutamine infusions (intracoronary or peripheral).
  • The nitric oxide synthase inhibitor, NG-monomethyl-L-arginine (L-NMMA), was infused intracoronary.
  • Left ventricular pressure and dP/dt were measured to assess contractility.

Main Results:

  • Intracoronary dobutamine increased LV peak +dP/dt by 33%.
  • L-NMMA alone did not affect baseline cardiac function.
  • Concurrent L-NMMA infusion potentiated dobutamine's effect on +dP/dt by 30-37%.

Conclusions:

  • Heart-derived nitric oxide (NO) attenuates the positive inotropic response to beta-adrenergic stimulation in humans with LV dysfunction.
  • NO may play a role in the reduced responsiveness to beta-adrenergic agents seen in these patients.
Abstract

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