Prolonged morphine treatment selectively increases membrane recruitment of delta-opioid receptors in mouse basal ganglia.
In recent years, we demonstrated that prolonged (48-h) treatment of rats or mice with selective m-opioid receptor ((mu)OR) agonists induced a translocation of delta-opioid receptors ((delta)ORs) from intracellular compartments to neuronal plasma membranes in the dorsal horn of the spinal cord. It remained to be determined whether this phenomenon also occurred in the brain. To resolve this issue, we analyzed by immunogold histochemistry the subcellular distribution of (delta)ORs in the nucleus accumbens, dorsal neostriatum, and frontal cortex in mice treated or not with morphine (48 h). We observed that prolonged treatment with morphine induced a translocation of (delta)ORs from intracellular to subplasmalemmal and membrane compartments in dendrites from both the nucleus accumbens and the dorsal neostriatum but not from the frontal cortex. We propose that this (mu)OR-(delta)OR interaction might prolong and modulate the sensitivity of neurons to opiates in specific target regions.
Lucido
Anna Lisa
AL
Montreal Neurological Institute and Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada, H3A 2B4.
Morinville
Anne
A
Gendron
Louis
L
Stroh
Thomas
T
Beaudet
Alain
A
D000701:Analgesics, Opioid / Q000494:pharmacology*; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism / Q000648:ultrastructure; D005260:Female; D005625:Frontal Lobe / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008854:Microscopy, Electron; D009020:Morphine / Q000494:pharmacology*; D017072:Neostriatum / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D009714:Nucleus Accumbens / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D021381:Protein Transport / Q000187:drug effects; D017465:Receptors, Opioid, delta / Q000378:metabolism*
D000701:Analgesics, Opioid; D017465:Receptors, Opioid, delta; D009020:Morphine