PT  - JOURNAL ARTICLE
AU  - Olga Pol
AU  - Francesc Alameda
AU  - Margarita M. Puig
TI  - Inflammation Enhances μ-Opioid Receptor Transcription and Expression in Mice Intestine
AID  - 10.1124/mol.60.5.894
DP  - 2001 Nov 01
TA  - Molecular Pharmacology
PG  - 894--899
VI  - 60
IP  - 5
4099  - http://molpharm.aspetjournals.org/content/60/5/894.short
4100  - http://molpharm.aspetjournals.org/content/60/5/894.full
SO  - Mol Pharmacol2001 Nov 01; 60
AB  - Opioid receptors (ORs) and their mRNA are present in the central and peripheral nervous systems of mammals and in different peripheral tissues, including the gut. Using a model of croton oil-induced (CO) intestinal inflammation in mice, we have shown a 6-fold increase in the potency of the antitransit and antisecretory effects of μ-OR agonists, mediated by peripheral ORs. We postulate that the enhanced effects are mediated by an increase in the expression of intestinal OR. We used jejunum (stripped of the mucosal layer) from mice with CO-induced intestinal inflammation and, as control subjects, saline-treated animals (SS). We evaluated the quantity of μ-OR mRNA determined by a competitive reverse-transcriptase polymerase chain reaction; the levels of μ-OR protein by Western blot immunoassay, and the localization and number of cells expressing μ-OR using immunohistochemistry. The results show a significant increase of μ-OR mRNA (7.7-fold) and receptor protein (3-fold) during intestinal inflammation. Inflammation also induced a 64.3% increase in the number of neurons expressing μ-OR immunoreactivity in the myenteric plexus but not in the submucosal plexus. Our results show that intestinal inflammation enhances the transcription and translation of μ-OR mRNA, thus explaining the increased potency of μ-opioids during inflammation.