Date Thesis Awarded

5-2020

Document Type

Honors Thesis

Degree Name

Bachelors of Science (BS)

Department

Neuroscience

Advisor

Joshua Burk

Committee Members

Robin Looft-Wilson

Paul Kieffaber

Abstract

The orexin (also called hypocretin) system projects to a wide array of brain regions and is activated by drugs of abuse. The orexin system is best known for its function in wakefulness and arousal, but recent research has suggested that orexins play a vital role in attentional processing. The orexin-1 receptor has been implicated in crucial mechanisms of attention, specifically the transmission of acetylcholine to the cortex. Nicotine is a commonly administered psychoactive drug that has been shown to have cognitive-enhancing effects. Nicotine appears to target the orexin system, suggesting a potential role of the orexin system in mediating the cognitive enhancing effects seen with nicotine. However, the role of orexinergic function in the attentional-promoting effects of nicotine has not been fully described. The present study was designed with two goals in mind: 1) to identify a nicotine dose that improves rat performance in a sustained-attention task and 2) to examine the effect of chronic nicotine administration in conjunction with a selective orexin-1 antagonist, SB-334867, in rats in a sustained-attention task. The results of these experiments suggest that acute nicotine administration impairs attentional functioning, and that chronic nicotine administration slightly improves performance in the sustained-attentional task. Administration of chronic nicotine with SB-334867 blocks the beneficial effect of chronic nicotine in the sustained-attention task. Although these data are preliminary, the findings of this study could provide a novel target that mimics nicotine-induced cognitive activation and give insight into the behavioral and attentional effects of nicotinic activation and orexin-1 antagonism.

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