The Effect And Mechanism Of Hypothalamic Paraventricular Nucleus Orexin-A On Body Weight And Free Movement In Rats

Objective: To investigate the effect of orexin-A microinjected into the paraventricular nucleus of the hypothalamus(PVN) on body weight in rats.Methods: Chronic guide cannulae were implanted into PVN of rats. Orexin-A was microinjected into the brain site. The effect of orexin-A on body weight in rats was detected.Results: The loss of body weight in orexin-A-treated rats was more significantly than their vehicle-injected counterparts(P<0.05), but they had no difference in food intake(P?0.05). The rats were more significantly active after intra-PVN orexin microinjection compared to vehicle(P<0.05). These results support the concept that orexinergic agents have the potential to produce negative energy balance through increasing physical activity.Conclusion: Orexin-A microinjected into the paraventricular nucleus of the hypothalamus(PVN) can induce weight loss in rats through producing negative energy balance via the increase of physical activity.