Opioid agonist-antagonist effect of naloxone in modulating rabbit jejunum contractility in vitro

• Autorzy: Cosola C. , Albrizio M. , Guaricci A.C. , De Salvia M.A. , Zarrilli A. , Sciorsci R.L. , Minoia R.
• Języki publikacji: EN

Abstrakty

EN

Opioid peptides are the most effective drugs in controlling pain; their action is elicited by binding to specific membrane receptors. The gastrointestinal tract represents, after the nervous system, the site in which the opioid receptors are expressed at high levels. The opioid agonist morphine has a significant inhibitory effect on intestinal motility, this action is blocked by naloxone an opioid antagonist mainly active at mu and kappa receptors. In this study the presence of mu opioid receptor on rabbit jejunum was investigated by western blot. The effects of beta-endorphin, the endogenous opioid peptide with the highest affinity to the mu opioid receptor and those of naloxone on spontaneous rabbit jejunum contractions were evaluated. Beta-endorphin (10-6M) showed a relaxant effect on jejunum contractility while naloxone showed a dual effect inducing an increase of spontaneous contractility at low concentrations (10-6M, 10-7M, 10-8M) and a decrease when high concentrations (10-3M, 10-4M, 10-5M) were utilized. The obtained results demonstrate that mu opioid receptor is expressed in rabbit jejunum and suggest that this receptor may be involved in mediating the effects of both opioid agonist and antagonist on jejunum contractions.

Słowa kluczowe

EN

naloxone; gastrointestinal tract; opioid peptide; opioid; nervous system; jejunum; in vitro; rabbit; beta-endorphin

• Wydawca: -
• Czasopismo: Journal of Physiology and Pharmacology
• Rocznik: 2006
• Tom: 57
• Numer: 3
• Opis fizyczny: p.439-449,fig.,ref.

Twórcy

autor

Cosola C.

• Universita degli Studi di Bari, Str.Prov.Casamassima Km 3, 70010 Valenzano, Bari, Italy

autor

Albrizio M.

autor

Guaricci A.C.

autor

De Salvia M.A.

autor

Zarrilli A.

autor

Sciorsci R.L.

autor

Minoia R.