Seda GÜNDÜZ BAŞÇIL, Asuman GÖLGELİ
Hacettepe University Journal of the Faculty of Pharmacy - 2026;46(3):195-204
This study aims to investigate the effects of Vitamin D and EB1089 (seocalcitol), a synthetic vitamin D receptor agonist, on morphine-induced analgesia and the development of morphine tolerance in rats using thermal antinociceptive assays and plasma serotonin analysis. A total of 56 male Wistar albino rats weighing 240-260 g were used in the study. The rats were randomly assigned to 7 groups, with 8 rats in each group. Evaluation of antinociceptive activity was performed using the tail flick and hot plate methods. Serotonin levels in plasma were analyzed using the ELISA method. In the tail flick test, the morphine + vitamin D group exhibited significant analgesia compared to the control group. In the hot plate test both the morphine + vitamin D and morphine + EB1089 groups exhibited significant analgesia compared to both the control and morphine groups. Both the morphine tolerance + vitamin D and morphine tolerance + EB1089 groups showed a significant increase in pain threshold in the tail flick and hot plate tests compared to the control and morphine tolerance groups. This study demonstrates that vitamin D and EB1089 enhance the analgesic effects of morphine in rats and slow the development of morphine tolerance.
