Involvement of Neuropeptide Orexin B in Basolateral Amygdala Mediated Consummatory Behaviour in Male Wistar Albino Rats.

ABSTRACT

The basolateral amygdala has been implicated in the regulation of food intake besides the hypothalamic centres. In the present study, we hypothesized that the Orexin B, a polypeptide identified in the lateral hypothalamic region, may be involved in the modification of the functions the of amygdaloid centres. We therefore studied the effect of infusion of Orexin B and its antagonist (TCS-OX2-29) into Basolateral amygdala to study the feeding behaviour. Materials and methods: Adult male Wistar albino rats were selected and grouped into control, sham operated control and experimental groups (n=6 each) Orexin was infused in two doses (3 nmol/μl, 30 nmol/ μl) and TCS-OX2-29(10 μg/μl) was infused in another group. Sequential Food intake and water intake were measured at 1, 2, 4, 6, 12 hours and intake for the day was also recorded in all groups and the results (mean±SEM) were statistically analyzed by Kruskal Wali’s test and p<0.05 was considered significant. Results: The food intake and water intake were significantly increased (p<0.01) in the high dose group though the increase in the low dose treated animals was less. Injection of Orexin B antagonist decreased the food and water intake significantly. Discussion and conclusion: The results suggest that Orexin plays a role in the modulation of feeding behaviour. In the lower doses it did not show significant effect. At higher doses, the effect was marked. The role of orexin in ingestive behaviour is further confirmed by the action of antagonist infusion, which resulted decrease in the feeding activities.