Effects of the BDNF Val66Met polymorphism on anxiety-like behavior following nicotine withdrawal in mice

Abstract

Introduction: Nicotine withdrawal is characterized by both affective and cognitive symptoms. Identifying genetic polymorphisms that could affect the symptoms associated with nicotine withdrawal are important in predicting withdrawal sensitivity and identifying personalized cessation therapies. In the current study we used a mouse model of a non-synonymous single nucleotide polymorphism in the translated region of the brain-derived neurotrophic factor (BDNF) gene that substitutes a valine (Val) for a methionine (Met) amino acid (Val66Met) to examine the relationship between the Val66Met single nucleotide polymorphism and nicotine dependence. Methods: This study measured proBDNF and the BDNF prodomain levels following nicotine and nicotine withdrawal and examined a mouse model of a common polymorphism in this protein (BDNFMet/Met) in three behavioral paradigms: Novelty-induced hypophagia, marble burying, and the open-field test. Results: Using the BDNF knock-in mouse containing the BDNF Val66Met polymorphism we found: (1) blunted anxiety-like behavior in BDNFMet/Met mice following withdrawal in three behavioral paradigms: Novelty-induced hypophagia, marble burying, and the open-field test; (2) the anxiolytic effects of chronic nicotine are absent in BDNFMet/Met mice; and (3) an increase in BDNF prodomain in BDNFMet/Met mice following nicotine withdrawal. Conclusions: Our study is the first to examine the effect of the BDNF Val66Met polymorphism on the affective symptoms of withdrawal from nicotine in mice. In these mice, a single-nucleotide polymorphism in the translated region of the BDNF gene can result in a blunted withdrawal, as measured by decreased anxiety-like behavior. The significant increase in the BDNF prodomain in BDNFMet/Met mice following nicotine cessation suggests a possible role of this ligand in the circuitry remodeling after withdrawal.