Figure 1.

Experimental scheme. Graph illustrating experimental conditions in the study. Six male Wistar rats were treated with 0.5 mg/kg morphine (dark gray bar) or 10 µg/kg fentanyl (light gray bar) for 60 min before the left renal pedicle was occluded for 45 min to promote ischemia and a 24 h reperfusion period. As controls we performed a sham group (white bar) and ischemia-reperfusion injury (IRI) without preconditioning (black bar). The gray scale identification is preserved in all figures. Blood and kidney tissue samples were collected at the end of the reperfusion period.