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Mu but not delta and kappa opioid receptor involvement in ventrolateral orbital cortex opioid-evoked antinociception in formalin test rats.
Neuroscience. 2004; 126(3):717-26.N

Abstract

The present study was designed to investigate the roles of different subtypes of opioid receptors in ventrolateral orbital cortex (VLO) opioid-evoked antinociception in formalin test by using an automatic detection system for recording the nociceptive behavior (agitation) and a manual method for detecting the duration of licking the injected paw in the conscious rat. Formalin (5%, 50 microl) s.c. injected into the hindpaw produced a biphasic agitation response or lengthening duration of licking. Morphine (5 microg) microinjected unilaterally into VLO significantly inhibited the agitation response and the licking time, and these effects were blocked by pre-administration of the non-selective opioid receptor antagonist naloxone (1.0 microg) into the same site. Microinjection of endomorphin-1 (5 microg), a selective micro-receptor agonist, and [D-Ala2, D-Leu5]-enkephalin (DADLE, 10 microg), a delta-/micro-receptor agonist also inhibited the nociceptive behaviors, and both the effects were blocked by selective mu-receptor antagonist beta-funaltrexamine hydrochloride (beta-FNA; 3.75 microg), but the DADLE-evoked inhibition was not influenced by the selective delta-receptor antagonist naltrindole (5 microg). Microinjection of selective kappa-receptor agonist (+/-)-trans-U-50488 methanesulfonate salt (1.5 microg) failed to alter the nociceptive behaviors induced by formalin injection. The beta-FNA and naloxone applied into VLO and morphine into the adjacent regions ventral and dorsal to VLO had no effect on the formalin-evoked nociceptive behaviors. These results suggest that mu- but not delta- or kappa-opioid receptor is involved in the VLO opioid-evoked antinociception in formalin test rat.

Authors+Show Affiliations

Department of Physiology, School of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, PR China.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

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

Language

eng

PubMed ID

15183520

Citation

Xie, Y F., et al. "Mu but Not Delta and Kappa Opioid Receptor Involvement in Ventrolateral Orbital Cortex Opioid-evoked Antinociception in Formalin Test Rats." Neuroscience, vol. 126, no. 3, 2004, pp. 717-26.
Xie YF, Wang J, Huo FQ, et al. Mu but not delta and kappa opioid receptor involvement in ventrolateral orbital cortex opioid-evoked antinociception in formalin test rats. Neuroscience. 2004;126(3):717-26.
Xie, Y. F., Wang, J., Huo, F. Q., Jia, H., & Tang, J. S. (2004). Mu but not delta and kappa opioid receptor involvement in ventrolateral orbital cortex opioid-evoked antinociception in formalin test rats. Neuroscience, 126(3), 717-26.
Xie YF, et al. Mu but Not Delta and Kappa Opioid Receptor Involvement in Ventrolateral Orbital Cortex Opioid-evoked Antinociception in Formalin Test Rats. Neuroscience. 2004;126(3):717-26. PubMed PMID: 15183520.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Mu but not delta and kappa opioid receptor involvement in ventrolateral orbital cortex opioid-evoked antinociception in formalin test rats. AU - Xie,Y F, AU - Wang,J, AU - Huo,F Q, AU - Jia,H, AU - Tang,J S, PY - 2004/04/15/accepted PY - 2004/6/9/pubmed PY - 2004/9/15/medline PY - 2004/6/9/entrez SP - 717 EP - 26 JF - Neuroscience JO - Neuroscience VL - 126 IS - 3 N2 - The present study was designed to investigate the roles of different subtypes of opioid receptors in ventrolateral orbital cortex (VLO) opioid-evoked antinociception in formalin test by using an automatic detection system for recording the nociceptive behavior (agitation) and a manual method for detecting the duration of licking the injected paw in the conscious rat. Formalin (5%, 50 microl) s.c. injected into the hindpaw produced a biphasic agitation response or lengthening duration of licking. Morphine (5 microg) microinjected unilaterally into VLO significantly inhibited the agitation response and the licking time, and these effects were blocked by pre-administration of the non-selective opioid receptor antagonist naloxone (1.0 microg) into the same site. Microinjection of endomorphin-1 (5 microg), a selective micro-receptor agonist, and [D-Ala2, D-Leu5]-enkephalin (DADLE, 10 microg), a delta-/micro-receptor agonist also inhibited the nociceptive behaviors, and both the effects were blocked by selective mu-receptor antagonist beta-funaltrexamine hydrochloride (beta-FNA; 3.75 microg), but the DADLE-evoked inhibition was not influenced by the selective delta-receptor antagonist naltrindole (5 microg). Microinjection of selective kappa-receptor agonist (+/-)-trans-U-50488 methanesulfonate salt (1.5 microg) failed to alter the nociceptive behaviors induced by formalin injection. The beta-FNA and naloxone applied into VLO and morphine into the adjacent regions ventral and dorsal to VLO had no effect on the formalin-evoked nociceptive behaviors. These results suggest that mu- but not delta- or kappa-opioid receptor is involved in the VLO opioid-evoked antinociception in formalin test rat. SN - 0306-4522 UR - https://www.unboundmedicine.com/medline/citation/15183520/Mu_but_not_delta_and_kappa_opioid_receptor_involvement_in_ventrolateral_orbital_cortex_opioid_evoked_antinociception_in_formalin_test_rats_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0306452204002787 DB - PRIME DP - Unbound Medicine ER -