Effect of diabetes on the antinociceptive effect of beta-endorphin.
We examined whether streptozotocin-induced diabetes can modulate beta-endorphin-induced antinociception in mice. While beta-endorphin administered i.c.v. produced a dose-dependent inhibition of the tail-flick response in both diabetic and non-diabetic mice, the antinociceptive response was greater in diabetic mice than in non-diabetic mice. The ED50 value of beta-endorphin administered i.c.v. in diabetic mice was significantly lower than that in non-diabetic mice. The antinociceptive effects of beta-endorphin administered i.c.v. in both diabetic and non-diabetic mice were significantly antagonized by s.c. administration of naltrindole, a selective delta-opioid receptor antagonist. beta-Endorphin administered i.t. also produced a dose-dependent antinociception in both diabetic and non-diabetic mice. However, the ED50 value of kappa-opioid receptor antagonist. On the other hand, the antinociceptive potency of DPDPE, a selective delta-opioid agonist, administered i.t. is significantly increased in diabetic mice, as compared with non-diabetic mice, whereas, the antinociceptive potency of U-50,488H, a kappa-opioid receptor agonist, administered i.t. is significantly less than in non-diabetic mice. These results suggest that diabetes may modulate beta-endorphin-induced antinociception differently at the spinal and supraspinal levels.
Kamei
J
J
Department of Pharmacology, Faculty of Pharmaceutical Sciences, Hoshi University, Tokyo, Japan.
Kawashima
N
N
Hitosugi
H
H
Misawa
M
M
Nagase
H
H
Kasuya
Y
Y
D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer; D000700:Analgesics / Q000494:pharmacology*; D000818:Animals; D002552:Cerebral Ventricles / Q000187:drug effects* / Q000502:physiology / Q000503:physiopathology; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology*; D004305:Dose-Response Relationship, Drug; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D020881:Enkephalin, D-Penicillamine (2,5)-; D004745:Enkephalins / Q000494:pharmacology; D007276:Injections, Intraventricular; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D009271:Naltrexone / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology*; D010146:Pain / Q000503:physiopathology / Q000517:prevention & control*; D011759:Pyrrolidines / Q000494:pharmacology; D012016:Reference Values; D001615:beta-Endorphin / Q000008:administration & dosage / Q000494:pharmacology*
D000700:Analgesics; D004745:Enkephalins; D009292:Narcotic Antagonists; D011759:Pyrrolidines; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D009271:Naltrexone; D001615:beta-Endorphin; D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer; D020881:Enkephalin, D-Penicillamine (2,5)-; C055382:naltrindole