Differential mediation of cold water swim stress-induced antinociception by delta-opioid receptor subtypes in diabetic mice.
The involvement of delta-opioid receptor subtypes in cold water swim stress (CWSS)-induced antinociception in diabetic mice was compared with that in non-diabetic mice. Three-minute swim stress produced significant antinociception in both diabetic and non-diabetic mice as determined by the tail-pinch test. However, the extent of CWSS-induced antinociception in diabetic mice was significantly greater than that in non-diabetic mice. Pretreatment with naltriben, a selective delta 2-opioid receptor antagonist, significantly attenuated CWSS-induced antinociception in both non-diabetic and diabetic mice. In contrast, although 7-benzylidenenaltrexone, a selective delta 1-opioid receptor antagonist, significantly attenuated CWSS-induced antinociception in diabetic mice, it had no effect in non-diabetic mice. These results suggest that CWSS-induced antinociception in non-diabetic mice is mediated by delta 2-opioid receptors, whereas CWSS-induced antinociception in diabetic mice is mediated by both delta 1- and delta 2-opioid receptors. Furthermore, the enhanced CWSS-induced antinociception in diabetic mice may be due to the activation of delta 1-opioid receptors.
Kamei
J
J
Department of Pharmacology, Faculty of Pharmaceutical Sciences, Hoshi University, Tokyo, Japan.
Iwamoto
Y
Y
Hitosugi
H
H
Misawa
M
M
Nagase
H
H
Kasuya
Y
Y
D000698:Analgesia; D000818:Animals; D001597:Benzylidene Compounds / Q000494:pharmacology; D003080:Cold Temperature; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology*; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D009271:Naltrexone / Q000031:analogs & derivatives / Q000494:pharmacology; D017465:Receptors, Opioid, delta / Q000502:physiology*; D013311:Streptozocin; D013312:Stress, Physiological / Q000503:physiopathology*; D013550:Swimming
D001597:Benzylidene Compounds; D017465:Receptors, Opioid, delta; C077358:7-benzylidenenaltrexone; D009271:Naltrexone; D013311:Streptozocin