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Assessment of nociceptin/orphanin FQ and micro-opioid receptor mRNA in the human right atrium

J McDonald1, A D Leonard, A Serrano-Gomez

  • 1Department of Cardiovascular Sciences (Pharmacology and Therapeutics Group), Division of Anaesthesia, Critical Care and Pain Management, University of Leicester, Leicester Royal Infirmary, Leicester, UK.

British Journal of Anaesthesia
|April 24, 2010
PubMed
Abstract

Insights

The human right atrium expresses mRNA for nociceptin/orphanin FQ (NOP) receptors and low levels of micro (mu: MOP) opioid receptors. Receptor expression did not correlate with cardiac function in patients with heart failure.

Area of Science:

  • Cardiology
  • Pharmacology
  • Molecular Biology

Background:

  • The presence of micro (mu: MOP) and nociceptin/orphanin FQ (NOP) receptors in the human myocardium is debated.
  • This study investigated the expression of these receptors and their precursor in human atrial tissue.

Purpose of the Study:

  • To determine the expression of NOP and MOP receptor mRNA in the human right atrium.
  • To investigate the presence of mRNA for the NOP precursor peptide, ppN/OFQ.
  • To correlate receptor expression with cardiac function, specifically left ventricular ejection fraction (LVEF).

Main Methods:

  • Quantitative real-time PCR (Q-PCR) was used to measure mRNA levels of NOP, MOP, and ppN/OFQ in human right atrial biopsies.
  • Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) served as the housekeeper gene for normalization.
  • Patients were categorized based on LVEF (normal >50% vs. impaired <50%) to assess correlations.

Main Results:

  • NOP receptor mRNA was detected in 38 out of 40 patients, with significantly higher expression than MOP receptor mRNA (detected in 29 patients).
  • ppN/OFQ mRNA was detected in only 10 patients, indicating its absence or very low levels.
  • No significant difference in NOP or MOP mRNA expression was observed between patients with normal and impaired LVEF, nor was there a correlation with intraoperative LVEF estimates.

Conclusions:

  • The human right atrium expresses mRNA for NOP receptors and potentially low levels of MOP receptors.
  • The expression of these receptors in the atrium does not appear to be linked to the degree of cardiac dysfunction.
  • ppN/OFQ mRNA was not found to be expressed in the human atrium.

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