The Effects of Oral Chronic Nicotine Administration and Withdrawal on Neuropeptide Y Receptor Expression in Rat Brain
Project no. 20469 · Status: Kapanmış · 2019
Summary
Rationale: Smoking creates feeding and weight suppression in humans that often rebound with negative affective symptoms following cessation. These symptoms of withdrawal and fear of weight gain often cause avoiding trying to quit smoking. Nicotine treatment produces similar effects in rats, but the neural mechanisms responsible are not fully known. Recent evidence shows that mesocorticolimbic levels of neuropeptide Y and its receptors change with nicotine administration. As a well known orexigenic and anxiety-related peptide, NPY and its receptors could have a role in reward and withdrawal pathways. Objective: To characterize potential differences in PFC and HIP NPY-Y2 receptor mRNA expression levels that occur with oral chronic nicotine treatment on reward and withdrawal phases. Methods: In the preliminary study, four groups of male Sprague Dawley rats (n=40) were subjected to oral chronic nicotine administration for 12 weeks (25 µg/ml or 50 µg/ml per week). Then, collected brain tissues used for this study. qRT-PCR utilized to measure Y2 mRNA expression levels of rat PFC and HIP tissues. Results: The reward phase of nicotine treatment didn't affect NPY Y2 mRNA expression in subjected areas, followed by a significant increase in PFC mRNA expression after 48-hour-withdrawal of nicotine compared to the reward and control groups. Albeit, there were no significant changes in the 24-hour-withdrawal group, it can be seen from the results that the increase started from the first day of withdrawal. We also report that there were no significant changes in HIP NPY2R mRNA expression levels among groups. Conclusions: These findings provide molecular support that changes in PFC–NPY2R may play a functional role in nicotine withdrawal. Keywords; Nicotine ; Neuropeptide Y; Neuropeptide Y2 Receptor; Substance Withdrawal ; Nicotine Dependence