Behavioral consequences of delta-opioid receptor activation in the periaqueductal gray of morphine tolerant rats
Chronic morphine administration shifts delta-opioid receptors (DORs) from the cytoplasm to the plasma membrane. Given that microinjection of morphine into the PAG produces antinociception, it is hypothesized that the movement of DORs to the membrane will allow antinociception to the DOR agonist delt...
| Publié dans: | Neural plasticity. - 1998. - 2009(2009) vom: 24., Seite 516328 |
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| Auteur principal: | |
| Autres auteurs: | , , |
| Format: | Article en ligne |
| Langue: | English |
| Publié: |
2009
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| Accès à la collection: | Neural plasticity |
| Sujets: | Journal Article Research Support, N.I.H., Extramural Research Support, Non-U.S. Gov't Oligopeptides Receptors, Opioid, delta deltorphin II, Ala(2)- 122752-16-3 Morphine 76I7G6D29C |
| Résumé: | Chronic morphine administration shifts delta-opioid receptors (DORs) from the cytoplasm to the plasma membrane. Given that microinjection of morphine into the PAG produces antinociception, it is hypothesized that the movement of DORs to the membrane will allow antinociception to the DOR agonist deltorphin II as a way to compensate for morphine tolerance. Tolerance was induced by twice daily injections of morphine (5, 10, or 20 mg/kg, subcutaneous) for 3.5 days. Microinjection of deltorphin into the vPAG 6 hours after the last morphine injection produced a mild antinociception that did not vary in a consistent manner across morphine pretreatment doses or nociceptive tests. In contrast, deltorphin caused a decrease in activity in morphine tolerant rats that was associated with lying in the cage. The decrease in activity and change in behavior indicate that chronic morphine administration alters DORs in the vPAG. However, activation of these receptors does not appear to compensate for the decrease in antinociception caused by morphine tolerance |
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| Description: | Date Completed 09.04.2009 Date Revised 20.10.2021 published: Print-Electronic Citation Status MEDLINE |
| ISSN: | 1687-5443 |
| DOI: | 10.1155/2009/516328 |