Changes in nociceptin/orphanin FQ levels in rat brain regions after acute and chronic cannabinoid treatment in conjunction with the development of antinociceptive tolerance
Küçük Resim Yok
Tarih
2016
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Wiley-Blackwell
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
It has been indicated that acute and chronic morphine administrations enhance nociceptin/orphanin FQ (N/OFQ) levels in the brain, which might play role in the development of tolerance to the antinociceptive effect of morphine. Accordingly, N/OFQ receptor (NOP) antagonists have been shown to prevent the development of antinociceptive tolerance to morphine. Our aim is to observe whether cannabinoids, similarly to opioids, enhance N/OFQ levels in pain-related brain regions and whether antagonism of NOP receptors attenuates the development of tolerance to the antinociceptive effect of cannabinoids. Hot plate and Tail flick tests are used to assess the antinociceptive response in Sprague-Dawley rats. N/OFQ levels are measured in cortex, amygdala, hypothalamus, periaqueductal gray, nucleus raphe magnus and locus coeruleus of rat brains using Western blotting and immunohistochemistry. Within 9 days, animals became completely tolerant to the antinociceptive effect of the cannabinoid agonist WIN 55,212-2 (2, 4, 6 mg/kg, i.p.). Chronic administration of JTC-801, a NOP receptor antagonist, at a dose that exerted no effect on its own (1 mg/kg, i.p.), attenuated development of tolerance to the antinociceptive effect of WIN 55,212-2 (4 mg/kg, i.p.). Western blotting and immunohistochemistry results showed that N/OFQ levels significantly increased in amygdala, periaqueductal gray, nucleus raphe magnus and locus coeruleus of rat brains when WIN 55,212-2 was combined with JTC-801. We hypothesize that, similar to opioids, chronic cannabinoid + NOP antagonist administration may enhance N/OFQ levels and NOP receptor antagonism prevents development of tolerance to cannabinoid antinociception.
Açıklama
Anahtar Kelimeler
Antinociceptive Effect, Cannabinoid, Immunohistochemistry, Nociceptin, Orphanin FQ, Tolerance, Western Blotting, Nitric-Oxide Production, Neuropathic Pain, Morphine-Tolerance, Opioid Tolerance, Nerve Injury, Cellular Mechanisms, Receptor Agonists, Precursor Protein, Mice, Dependence
Kaynak
Fundamental & Clinical Pharmacology
WoS Q Değeri
Q3
Scopus Q Değeri
Q2
Cilt
30
Sayı
6
