mu- but not delta- and kappa-opioid receptor mediates the nucleus submedius interferon-alpha-evoked antinociception in the rat.
Previous studies have indicated that interferon-alpha (IFN-alpha) can bind to opioid receptors and exerts an antinociceptive effect in both peripheral and central nervous systems. The current study investigated the antinociceptive effect of IFN-alpha unilaterally microinjected into the thalamic nucleus submedius (Sm) of rats on noxious thermal stimulus, and the roles of different subtypes of opioid receptors in mediating the Sm IFN-alpha-evoked antinociception. The results indicated that unilateral microinjection of IFN-alpha (4, 8, 16 pmol) into the Sm dose-dependently increased the hind paw withdrawal latency from the noxious heat stimulus, and this effect was reversed by pretreatment with non-selective opioid receptor antagonist naloxone (200 pmol) and specific mu-opioid receptor antagonist beta-FNA (1 nmol) into the same sites, whereas delta-opioid receptor antagonist ICI174,864 (1 nmol) and kappa-opioid receptor antagonist nor-BNI (1 nmol) failed to alter the effect of IFN-alpha. These results suggest that Sm is involved in IFN-alpha-evoked antinociception and mu- but not delta- and kappa-opioid receptor mediates the Sm IFN-alpha-evoked antinociception.
Wang
Jun-Yang
JY
Department of Immunology and Pathogenic Biology, Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi 710061, PR China.
Zeng
Xiao-Yan
XY
Fan
Gui-Xiang
GX
Yuan
Yu-Kang
YK
Tang
Jing-Shi
JS
D000818:Animals; D004924:Escape Reaction; D016898:Interferon-alpha / Q000494:pharmacology / Q000502:physiology*; D008297:Male; D020645:Mediodorsal Thalamic Nucleus / Q000378:metabolism / Q000502:physiology*; D008845:Microinjections; D009270:Naloxone / Q000494:pharmacology; D009271:Naltrexone / Q000031:analogs & derivatives / Q000494:pharmacology; D010146:Pain / Q000378:metabolism / Q000503:physiopathology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time; D017473:Receptors, Opioid, kappa / Q000037:antagonists & inhibitors / Q000502:physiology*; D017450:Receptors, Opioid, mu / Q000037:antagonists & inhibitors / Q000502:physiology*
D016898:Interferon-alpha; D017473:Receptors, Opioid, kappa; D017450:Receptors, Opioid, mu; D009270:Naloxone; D009271:Naltrexone; C024524:beta-funaltrexamine