Magnetic Resonance Imaging the Brain Structures Involved in Nicotine Susceptibility in Rats

Abstract

The aim of this study is to identify brain structures involved in the individual difference of nicotine susceptibility in rats with longitudinal magnetic resonance imaging (MRI). Adult male Sprague-Dawley rats were subjected to intermittent intraperitoneal nicotine injection for 14 days using a mini-osmotic pump, followed by forced withdrawal for 14 days. Somatic withdrawal behavioral signs test was performed on day 0, 15, and 29 to quantify nicotine dependence. Correlation analyses between the withdrawal behavior score and structural MRI indices on day 1 (baseline scan) revealed that the severity of nicotine dependence was negatively correlated with the gray matter (GM) volumes in bilateral prelimbic cortex/left granular insular cortex and the white matter volume in bilateral thalamus, but positively correlated with the GM volumes in right hippocampal CA1/left thalamus. It is proposed that the aforementioned structural indices may be used as biomarkers for nicotine susceptibility, predicting the risk of nicotine dependence before individuals are exposed to nicotine.

Keywords

• magnetic resonance imaging (mri)
• nicotine susceptibility
• brain structure
• withdrawal behavior