Figure 2. Effects of chronic morphine treatment and pair feeding on metabolic parameters of male rats.

Daily changes of food intake in placebo and morphine implanted animals. Pair fed rats were placebo implanted and received the same amount of food that was consumed by the morphine implanted pairs. n = 12, ⁺ p<0.05, ⁺⁺ p<0.01 morphine vs. placebo-implanted group (Student’s t-test) A. Mean (±SEM) values of daily changes in body weight of morphine implanted and placebo implanted and pair fed rats. Note that pair feeding of placebo implanted rats resulted in significantly more body weight loss compared to morphine implanted animals, n = 12, *p<0.05 placebo implanted vs. pair fed group (Student’s t-test).