Modification of morphine antinociceptive response by blood glucose status: possible involvement of cellular energetics.

The antinociceptive response to morphine was enhanced in insulin-hypoglycemic animals whereas it was decreased in diabetic or in hypertonic glucose-pretreated hyperglycemic animals. 3-O-Methylglucose was, however, without effect on morphine analgesia whereas 2-deoxyglucose sensitized this effect. Furthermore, as malate and isocitrate attenuated the morphine analgesic response of insulin hypoglycemic animals and 2,4-dinitrophenol sensitized this response in diabetic animals, it is possible that the blood glucose level affects the morphine analgesic response by affecting cellular energetics.