ANTINOCICEPTIVE EFFECT OF LIPOPOLYSACCHARIDE FROM PANTOEA AGGLOMERANSON STREPTOZOTOCIN-INDUCED DIABETIC MICE

The antinociceptive effect of lipopolysaccharide from Pantoea agglomer ans (LPSp) in streptozotocin-induced diabetic mice was examined. Altho ugh subcutaneous (s.c.) administration of LPSp produced a dose-depende nt inhibition of the tail-flick response in both non-diabetic and diab etic mice, the antinociceptive response was greater in diabetic mice t han in non-diabetic mice. The antinociceptive effects of LPSp in both diabetic and non-diabetic mice were significantly antagonized by s.c. administration of naltrindole, a selective delta-opioid receptor antag onist or nor-binaltorphimine, a selective kappa-opioid receptor antago nist, but not by beta-funaltrexamine, a selective mu-opioid receptor a ntagonist. These results suggest that LPSp produces a marked antinocic eptive effect in diabetic mice through the activation of delta- and ka ppa-opioid receptors.