Effect of Chronic Administration of Morphine on Male Rat's Feeding Behavior

Opiates regulate some body functions and behaviors. Chronic or acute abuses of morphine may have different body responses. Therefore, the aim of this study was to examine the acute and choronic effects of morphine administration on food consumpsion in male rats. 30 male spraugue-dawley rats with 250-300 g weight were randomly assigned in 3: control, acute and chronic (already addicted) groups. 12 h after fasting, morphine was injected for the acute and chronic, while the control group received normal saline. Then, each animal was put in test cages with water and food. Then, libitum and food consumption were measured at 15min intervals, until one hour, and also the amount of food intake 4 h after the injection. We found that administration of morphine (10 mg/ kg/ i.p) to acute (non-addicted group), caused a delay in feeding and decreased food intake in the first 60 minutes, but food intake increased at 4 h compared to control group. Conversely, administration of morphine (10 mg/ kg/ i.p) to chronic (addicted) male rats didnt cause a delay in food intake and increased food intake during the first 60 minutes. Moreover, at 4 h after the injection, the amount of food intake increased. This difference was significant in comparison to acute (non-addicted) and control groups.Discussion & Our study showed that opiates can alter feeding behaviors and the pattern of feeding responses to morphine differs in addicted rats from non-dependent rats. Morphine addiction also increases body sensitivity to its nutritional response in male rats.