Background: In this study effects of stress resulted from using independent and co-administration morphine and carbohydrate on serum cortisol levels in rat were investigated to determine the possible causal link between morphine, carbohydrate and serum cortisol level.

Materials and Methods: This experimental study was performed on 24 male Wistar rats (200-250 gr) divided to 3 groups (n=8). Morphine dependency was induced by increasing doses of morphine through intraperitioneal (IP) injection. Animals were injected 10,20,30,40,50,60 mg/kg morphine sulfate on days 1,2,3,4,5,6 respectively and dose of 60 mg/kg was repeated for 20 extra days (Mo group). Another group of animals received the same dose of morphine plus l gr/kg glucose per day through intraperitoneal (IP) injection (Mo+Glu group). Duration of experiment was 26 days.

Results: Significant increase in serum cortisol level was observed after long-term use of both morphine and co-administration of morphine and carbohydrate. However, this increase was higher in Mo+Glu group than morphine group. (16.57% vs. 11.55%, P<0.05)

Conclusion: long-term use of morphine, with or without carbohydrate, may increase serum cortisol level