%0 Journal Article %1 gendron_morphine_2006 %A Gendron, Louis %A Lucido, Anna Lisa %A Mennicken, Françoise %A O'Donnell, Dajan %A Vincent, Jean-Pierre %A Stroh, Thomas %A Beaudet, Alain %D 2006 %J The Journal of Neuroscience: The Official Journal of the Society for Neuroscience %K Animals Cell_Membrane Cells Cultured Drug Ganglia Male Morphine Opioid Pain Pain_Measurement Rats Receptors Spinal delta {Dose-Response}_Relationship {Sprague-Dawley} %N 3 %P 953--962 %R 10.1523/JNEUROSCI.3598-05.2006 %T Morphine and pain-related stimuli enhance cell surface availability of somatic delta-opioid receptors in rat dorsal root ganglia %U http://www.ncbi.nlm.nih.gov/pubmed/16421315 %V 26 %X The present study demonstrates that perikaryaldelta-opioid receptors (deltaORs) in rat dorsal root ganglion (DRG) neurons bind and internalize opioid ligands circulating in the CSF. Using confocal and electron microscopy, we found that prolonged morphine treatment increased the cell surface density of these perikaryal deltaORs and, by way of consequence, receptor-mediated internalization of the fluorescent deltorphin (DLT) analog omega-Bodipy 576/589 deltorphin-I 5-aminopentylamide (Fluo-DLT) in all three types of DRG neurons (small, medium, and large). In contrast, chronic inflammatory pain induced by the injection of complete Freund's adjuvant (CFA) into one hindpaw selectively increased Fluo-DLT internalization in small and medium-sized DRG neurons ipsilateral to the inflammation. Based on our previous studies in the spinal cord of mu-opioid receptor (muOR) knock-out mice, it may be assumed that the enhanced membrane recruitment of deltaORs observed after sustained morphine is attributable to stimulation of muORs. However, the selectivity of the effect induced by inflammatory pain suggests that it involves a different mechanism, namely a modality-specific and pain-related activation of C and Adelta fibers. Indeed, stimulation by capsaicin of transient receptor potential vanilloid 1 receptors, which are selectively expressed by small diameter (\textless 600 microm2) DRG neurons, increased Fluo-DLT internalization exclusively in this cell population. The present results, therefore, demonstrate that DRG neurons express perikaryal deltaORs accessible to CSF-circulating ligands and that the density and, hence, presumably also the responsiveness, of these receptors may be modulated by both pain-related stimuli and sustained exposure to muOR agonists.

@article{gendron_morphine_2006, abstract = {The present study demonstrates that perikaryaldelta-opioid receptors {(deltaORs)} in rat dorsal root ganglion {(DRG)} neurons bind and internalize opioid ligands circulating in the {CSF.} Using confocal and electron microscopy, we found that prolonged morphine treatment increased the cell surface density of these perikaryal {deltaORs} and, by way of consequence, receptor-mediated internalization of the fluorescent deltorphin {(DLT)} analog {omega-Bodipy} 576/589 {deltorphin-I} 5-aminopentylamide {(Fluo-DLT)} in all three types of {DRG} neurons (small, medium, and large). In contrast, chronic inflammatory pain induced by the injection of complete Freund's adjuvant {(CFA)} into one hindpaw selectively increased {Fluo-DLT} internalization in small and medium-sized {DRG} neurons ipsilateral to the inflammation. Based on our previous studies in the spinal cord of mu-opioid receptor {(muOR)} knock-out mice, it may be assumed that the enhanced membrane recruitment of {deltaORs} observed after sustained morphine is attributable to stimulation of {muORs.} However, the selectivity of the effect induced by inflammatory pain suggests that it involves a different mechanism, namely a modality-specific and pain-related activation of C and Adelta fibers. Indeed, stimulation by capsaicin of transient receptor potential vanilloid 1 receptors, which are selectively expressed by small diameter ({\textless} 600 microm2) {DRG} neurons, increased {Fluo-DLT} internalization exclusively in this cell population. The present results, therefore, demonstrate that {DRG} neurons express perikaryal {deltaORs} accessible to {CSF-circulating} ligands and that the density and, hence, presumably also the responsiveness, of these receptors may be modulated by both pain-related stimuli and sustained exposure to {muOR} agonists.}, added-at = {2011-08-03T21:06:35.000+0200}, author = {Gendron, Louis and Lucido, Anna Lisa and Mennicken, Françoise and {O'Donnell}, Dajan and Vincent, {Jean-Pierre} and Stroh, Thomas and Beaudet, Alain}, biburl = {https://www.bibsonomy.org/bibtex/269164b8c13bd609bfe91ada902289027/crc_chus}, doi = {10.1523/JNEUROSCI.3598-05.2006}, interhash = {3d0f22466d2140779b9d8b4fcaf3eaff}, intrahash = {69164b8c13bd609bfe91ada902289027}, issn = {1529-2401}, journal = {The Journal of Neuroscience: The Official Journal of the Society for Neuroscience}, keywords = {Animals Cell_Membrane Cells Cultured Drug Ganglia Male Morphine Opioid Pain Pain_Measurement Rats Receptors Spinal delta {Dose-Response}_Relationship {Sprague-Dawley}}, month = jan, note = {{PMID:} 16421315}, number = 3, pages = {953--962}, timestamp = {2011-08-03T21:10:03.000+0200}, title = {Morphine and pain-related stimuli enhance cell surface availability of somatic delta-opioid receptors in rat dorsal root ganglia}, url = {http://www.ncbi.nlm.nih.gov/pubmed/16421315}, volume = 26, year = 2006 }