Systemic ovalbumin sensitization downregulates norepinephrine uptake by rabbit aortic smooth muscle cells

Gabor Horvath, Aliza Torbati, Gregory E. Conner, Matthias Salathe, Adam Wanner

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Abstract

Norepinephrine (NE) concentration at α-adrenergic receptors is partially regulated by steroid-sensitive, extraneuronal catecholamine uptake (uptake-2). Because α1-adrenergic agonist-and glucocorticosteroid (GS)-induced bronchial vasoconstriction is enhanced in individuals with asthma, atopy could be associated with decreased uptake-2 by vascular smooth muscle cells (SMCs). We therefore evaluated whether NE uptake and its specific transporter messenger RNA (mRNA) were reduced in aortic SMCs of rabbits systemically sensitized with ovalbumin (OVA). NE uptake was measured using a semiquantitative fluorescence microscopic method. Corticosterone and O-methyl-isoprenaline, but not desipramine, co-incubation (1 μM each) for 20 min decreased NE uptake into SMCs, an inhibitor profile indicative of extraneuronal monoamine transporter (EMT). In OVA-sensitized rabbits, NE uptake was 25.9 ± 4.5% (mean ± SEM) lower than in control animals (P < 0.05). Sensitized serum had no effect on NE uptake into naive SMCs. EMT mRNA expression was measured in aortic smooth muscle, using multiplex reverse transcriptase-polymerase chain reaction. In OVA-sensitized rabbits, expression was 61.1 ± 16.4% lower than in control animals (P < 0.05). These data demonstrate that NE uptake by aortic SMCs is impaired in atopic rabbits, and associated with a decreased transporter mRNA expression. The same mechanism may operate in bronchial arteries in individuals with asthma.

Original languageEnglish (US)
Pages (from-to)746-751
Number of pages6
JournalAmerican journal of respiratory cell and molecular biology
Volume27
Issue number6
DOIs
StatePublished - Dec 1 2002

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ASJC Scopus subject areas

  • Molecular Biology
  • Pulmonary and Respiratory Medicine
  • Clinical Biochemistry
  • Cell Biology

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