Repository of Research and Investigative Information

Repository of Research and Investigative Information

Torbat Heydariyeh University of Medical Sciences

Persistent effects of the orexin-1 receptor antagonist SB-334867 on naloxone precipitated morphine withdrawal symptoms and nociceptive behaviors in morphine dependent rats

(2020) Persistent effects of the orexin-1 receptor antagonist SB-334867 on naloxone precipitated morphine withdrawal symptoms and nociceptive behaviors in morphine dependent rats. International Journal of Neuroscience. ISSN 00207454

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Official URL: https://www.scopus.com/inward/record.uri?eid=2-s2....

Abstract

Aim of the study: In this study, we investigated the effect of long-term administration of orexin receptor 1 (OXR1) antagonist on naloxone-precipitated morphine withdrawal symptoms and nociceptive behaviors in morphine-dependent rats. Materials and methods: Wistar rats received subcutaneous (s.c.) injections of morphine (6, 16, 26, 36, 46, 56, and 66 mg/kg, 2 ml/kg) at an interval of 24 h for 7 days. In chronic groups, the OXR1 antagonist, SB-334867 (20 mg/kg, i.p.), or its vehicle, was injected repetitively from postnatal day 1 (PND1)-PND23 and then for the following seven days before each morphine injection. Meanwhile, in acute groups, SB-334867, or its vehicle, was administered before each morphine injection. In groups of rats that were designated for withdrawal experiments, naloxone (2.5 mg/kg, i.p.) was administered after the last injection of morphine. In the formalin-induced pain, the effect of OXR1 inhibition on the antinociceptive effects of morphine was measured by injecting formalin after the final morphine injection. Results: Animals that received long-term SB-334867 administration before morphine injection demonstrated a significant reduction in chewing, defecation, diarrhea, grooming, teeth chattering, wet-dog shake, and writhing. Inhibiting OXR1 for a long time increased formalin-induced nociceptive behaviors in interphase and phase II of the formalin-induced pain. Conclusions: Our results indicated that the inhibition of OXR1 significantly reduces the development of morphine dependence and behavioral signs elicited by the administration of naloxone in morphine-dependent rats. Furthermore, the prolonged blockade of OXR1 might be involved in formalin-induced nociceptive behaviors. © 2020 Informa UK Limited, trading as Taylor & Francis Group.

Item Type: Article
Keywords: formalin-induced pain; morphine; nociceptive behaviors; Orexin receptor 1; withdrawal
Journal or Publication Title: International Journal of Neuroscience
Journal Index: ISI, Pubmed, Scopus
Publisher: Taylor and Francis Ltd
Identification Number: 10.1080/00207454.2020.1802266
ISSN: 00207454
Depositing User: دکتر محبوبه عبداللهی
URI: http://eprints.thums.ac.ir/id/eprint/2277

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