English

Abstract

AIM: Ventromedial hypothalamus and lateral hypothalamus are well known for their role in regulation of food intake. Septum is key component of limbic system which has reciprocal connections with lateral hypothalamus. These septal projections to lateral hypothalamus are thought to affect food intake. Opioid system is one of the systems affecting food intake. Agonists of Opioid receptors increase food intake while antagonists of these receptors decrease food intake. Also there is considerable amount of opioid receptors in septal nuclei and around area. Opioid antagonist naloxone is known to have hypophagic property, its mechanism of action being competitive blockade of opioid receptors in CNS. So the aim of the study was to find out the effect of septal lesion on naloxone induced hypophagia in Wistar rats. METHODS: After measuring the baseline food intake in 20 healthy adult male rats and 20 healthy adult female rats in the deprivation paradigm, the effect of naloxone on fasting animals was measured. Male and female rats were then subjected to septal lesions. After 10 days of operative recovery, the basal food intake and effect of naloxone injection on food intake after 24 hrs. of fasting was measured again. These observations were compared to those before the lesion. RESULTS: 1) It was confirmed that naloxone induces hypophagia in food deprived male and female rats. 2) Hypophagia was seen in initial hours in deprivation paradigms. 3) In rats there was no significant change in food intake after septal lesion. However, 4) after septal lesion, naloxone failed to induce hypophagia. CONCLUSION: 1) Naloxone induces hypophagia in deprived male and female rats. 2) Septal lesions do not alter food intake but they abolish hypophagic effect of naloxone in rats.