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Prolonged morphine treatment alters δ opioid receptor post-internalization trafficking
1Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada; Department of Anaesthesiology and Perioperative Care, University of California, Irvine, CA, USA.
British Journal of Pharmacology
|May 14, 2014
Summary
Prolonged morphine treatment alters δ opioid receptor (DOP receptor) trafficking by promoting MOP-DOP receptor interactions. This leads to increased cell surface DOP receptors with unique pharmacology and trafficking properties.
Area of Science:
- Neuroscience
- Pharmacology
- Cell Biology
Background:
- The δ opioid receptor (DOP receptor) is internalized constitutively and upon agonist binding.
- Previous studies indicated DOP receptors traffic to neuronal membranes after prolonged morphine exposure.
- This study investigates the post-internalization trafficking of DOP receptors following prolonged morphine treatment.
Purpose of the Study:
- To examine the effects of prolonged morphine treatment on the trafficking of DOP receptors after internalization.
- To understand the specific pathways and interactions involved in DOP receptor trafficking under different treatment conditions.
Main Methods:
- Primary cultures of dorsal root ganglia neurons were used.
- Co-localization of endogenous DOP receptors with post-endocytic compartments was measured.
- Acute and prolonged agonist treatments, including morphine, deltorphin II, SNC80, and DAMGO, were employed.
Main Results:
- Acute DOP receptor agonist treatment induced distinct post-endocytic sorting.
- Prolonged morphine treatment augmented constitutive DOP receptor trafficking.
- Morphine and MOP receptor agonists altered DOP receptor trafficking, an effect blocked by a DOP receptor antagonist.
Conclusions:
- Prolonged morphine treatment promotes MOP-DOP receptor interactions.
- This interaction augments the number of cell surface DOP receptors.
- The resulting MOP/DOP receptor species exhibits unique pharmacology and trafficking characteristics.
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