Activation of micro, delta or kappa opioid receptors by DAMGO, DPDPE, U-50488 or U-69593 respectively causes antinociception in the formalin test in the naked mole-rat (Heterocephalus glaber).
Date
2009-02Author
Towett, PK
Kanui, TI
Maloiy, GMO
Juma, F
Olongida, Ole Miaron J
Type
ArticleLanguage
enMetadata
Show full item recordAbstract
Data available on the role of the opioid systems of the naked mole-rat in nociception is scanty and unique compared to that of other rodents. In the current study, the effect of DAMGO, DPDPE and U-50488 and U-69593 on formalin-induced (20 microl, 10%) nociception were investigated. Nociceptive-like behaviors were quantified by scoring in blocks of 5 min the total amount of time (s) the animal spent scratching/biting the injected paw in the early (0-5 min) and in the late (25-60 min) phase of the test. In both the early and late phases, administration of 1 or 5 mg/kg of DAMGO or DPDPE caused a naloxone-attenuated decrease in the mean scratching/biting time. U-50488 and U-69593 at all the doses tested did not significantly change the mean scratching/biting time in the early phase. However, in the late phase U-50488 or U-69593 at the highest doses tested (1 or 5 mg/kg or 0.025 or 0.05 mg/kg, respectively) caused a statistically significant and naloxone-attenuated decrease in the mean scratching/biting time. The data showed that mu, delta or kappa-selective opioids causes antinociception in the formalin test in this rodent, adding novel information on the role of opioid systems of the animal on pain regulation.
URI
http://hinari-gw.who.int/whalecomwww.ncbi.nlm.nih.gov/whalecom0/pubmed/18929596http://erepository.uonbi.ac.ke:8080/xmlui/handle/123456789/40529
Citation
Pharmacol Biochem Behav. 2009 Feb;91(4):566-72.Publisher
University of Nairobi. Department of Animal Physiology