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mu- but not delta- and kappa-opioid receptors in the ventrolateral orbital cortex mediate opioid-induced antiallodynia in a rat neuropathic pain model.
Brain Res. 2006 Mar 03; 1076(1):68-77.BR

Abstract

Previous studies have indicated that the ventrolateral orbital cortex (VLO) is involved in opioid-mediated antinociception in the tail flick test and formalin test. The aim of the current study was to examine the effect of opioids microinjected into the VLO on allodynia in the rat L5/L6 spinal nerve ligation (SNL) model of neuropathic pain and determine the roles of different subtypes of opioid receptors in this effect. The allodynia was assessed by both mechanical (von Frey filaments) and cold plate (4 degrees C) stimuli. Morphine (1.0, 2.5, and 5.0 microg) microinjected into the VLO contralateral to the nerve ligation dose-dependently depressed the mechanical and cold allodynia and these effects were reversed by nonselective opioid receptor antagonist naloxone (1.0 microg) administrated into the same site. Microinjection of endomorphin-1 (5.0 microg), a highly selective mu-opioid receptor agonist, and [D-Ala2, D-Leu5]-enkephalin (DADLE, 10 microg), a delta-/mu-opioid receptor agonist, also depressed the allodynia, and the effects of both drugs were blocked by selective mu-receptor antagonist beta-funaltrexamine (beta-FNA, 3.75 microg), but the effects of DADLE were not influenced by the selective delta-receptor antagonist naltrindole (5.0 microg). Microinjection of U-62066 (100 microg), a kappa-opioid receptor agonist, into the VLO had no effect on the allodynia. These results suggest that the VLO is involved in opioid-induced antiallodynia and mu- but not delta- and kappa-opioid receptor mediates these effects in the rat with neuropathic pain.

Authors+Show Affiliations

Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi 710061, People's Republic of China.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

16476416

Citation

Zhao, Mei, et al. "Mu- but Not Delta- and Kappa-opioid Receptors in the Ventrolateral Orbital Cortex Mediate Opioid-induced Antiallodynia in a Rat Neuropathic Pain Model." Brain Research, vol. 1076, no. 1, 2006, pp. 68-77.
Zhao M, Wang JY, Jia H, et al. Mu- but not delta- and kappa-opioid receptors in the ventrolateral orbital cortex mediate opioid-induced antiallodynia in a rat neuropathic pain model. Brain Res. 2006;1076(1):68-77.
Zhao, M., Wang, J. Y., Jia, H., & Tang, J. S. (2006). Mu- but not delta- and kappa-opioid receptors in the ventrolateral orbital cortex mediate opioid-induced antiallodynia in a rat neuropathic pain model. Brain Research, 1076(1), 68-77.
Zhao M, et al. Mu- but Not Delta- and Kappa-opioid Receptors in the Ventrolateral Orbital Cortex Mediate Opioid-induced Antiallodynia in a Rat Neuropathic Pain Model. Brain Res. 2006 Mar 3;1076(1):68-77. PubMed PMID: 16476416.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - mu- but not delta- and kappa-opioid receptors in the ventrolateral orbital cortex mediate opioid-induced antiallodynia in a rat neuropathic pain model. AU - Zhao,Mei, AU - Wang,Jun-Yang, AU - Jia,Hong, AU - Tang,Jing-Shi, Y1 - 2006/02/13/ PY - 2005/09/27/received PY - 2006/01/05/revised PY - 2006/01/09/accepted PY - 2006/2/16/pubmed PY - 2006/7/26/medline PY - 2006/2/16/entrez SP - 68 EP - 77 JF - Brain research JO - Brain Res VL - 1076 IS - 1 N2 - Previous studies have indicated that the ventrolateral orbital cortex (VLO) is involved in opioid-mediated antinociception in the tail flick test and formalin test. The aim of the current study was to examine the effect of opioids microinjected into the VLO on allodynia in the rat L5/L6 spinal nerve ligation (SNL) model of neuropathic pain and determine the roles of different subtypes of opioid receptors in this effect. The allodynia was assessed by both mechanical (von Frey filaments) and cold plate (4 degrees C) stimuli. Morphine (1.0, 2.5, and 5.0 microg) microinjected into the VLO contralateral to the nerve ligation dose-dependently depressed the mechanical and cold allodynia and these effects were reversed by nonselective opioid receptor antagonist naloxone (1.0 microg) administrated into the same site. Microinjection of endomorphin-1 (5.0 microg), a highly selective mu-opioid receptor agonist, and [D-Ala2, D-Leu5]-enkephalin (DADLE, 10 microg), a delta-/mu-opioid receptor agonist, also depressed the allodynia, and the effects of both drugs were blocked by selective mu-receptor antagonist beta-funaltrexamine (beta-FNA, 3.75 microg), but the effects of DADLE were not influenced by the selective delta-receptor antagonist naltrindole (5.0 microg). Microinjection of U-62066 (100 microg), a kappa-opioid receptor agonist, into the VLO had no effect on the allodynia. These results suggest that the VLO is involved in opioid-induced antiallodynia and mu- but not delta- and kappa-opioid receptor mediates these effects in the rat with neuropathic pain. SN - 0006-8993 UR - https://www.unboundmedicine.com/medline/citation/16476416/mu__but_not_delta__and_kappa_opioid_receptors_in_the_ventrolateral_orbital_cortex_mediate_opioid_induced_antiallodynia_in_a_rat_neuropathic_pain_model_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0006-8993(06)00090-4 DB - PRIME DP - Unbound Medicine ER -