Document Type

Honors Project


Orexin has important functions in feeding, arousal, and motivation. However, the mechanism by which Orexin influences these processes is not well understood. The goals of the present study were: 1) demonstrate that orexin A enhances appetitive and consumptive behaviors (lever presses, licks, rewarded licks and breakpoint) using a progressive ratio schedule of reinforcement for sucrose reward and 2) Determine if gamma-aminobutyric acid receptor blockade could attenuate those behaviors. However, preliminary analysis did not reveal an effect of orexin A (30nM) when infused into the lateral ventricle of rats. Of the measures operant behaviors, the orexin A and saline groups did not differ. Therefore, the second phase was not conducted. Multiple explanations for the lack of orexin's effect are possible: aged rats, endogenous orexin levels, incorrect dose, misplaced cannula and use of a different schedule of reinforcement than that previously used with orexin. The unique function of orexin in these behaviors prompts further analysis into the reason behind the outcomes of this study.



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