The effects of cyclosporine on morphine-induced antinociception in diabetic mice.

The effects of cyclosporine on the antinociceptive effect of morphine were examined in diabetic mice. Sensitivities to the antinociceptive effect of morphine (5 mg/kg s.c.) in diabetic mice which had been pretreated with cyclosporine (30 mg/kg per day s.c.) for 14 days returned to those in vehicle-treated nondiabetic mice. Naive mice which had been injected with the supernatant of spleen cell homogenate (SSCH) from vehicle-treated diabetic mice were less sensitive to morphine-induced antinociception. However, adoptive transfer of SSCH from cyclosporine-treated diabetic mice to naive mice had no effect on the recipients' antinociceptive sensitivities to morphine. These results suggest that the abnormal antinociceptive effect of morphine and the immune responses of diabetic mice may somehow be related.