Expression analysis of hippocampal and amygdala CREB-BDNF signaling pathway in nicotine-induced reward under stress in rats.
Extensive research has shown that individuals are more sensitive to develop addiction and drug taking under stress state. The present study includes an expression analysis to identify the possible role of hippocampal and amygdala CREB (cAMP response element-binding protein) and BDNF (Brain-derived neurotrophic factor) activation in nicotine-induced conditioned place preference (CPP) under exposure to acute or sub-chronic stress. Using western-blot technique, CREB phosphorylation was shown to increase in the hippocampus and the amygdala following nicotine-induced CPP. The hippocampal level of BDNF was increased following nicotine administration and in the nicotine-treated animals exposed to acute stress. In animals exposed to acute stress, the amygdala ratios of the pCREB/CREB decreased, while pre-treatment of the animals with nicotine (0.1 mg/kg) decreased this ratio only in the hippocampus. Sub-chronic stress decreased the pCREB/CREB ratios in the hippocampus and the amygdala. Interestingly, sub-chronic stress-induced increase of nicotine reward only decreased the hippocampal pCREB/CREB ratio. The levels of BDNF in the hippocampus and the amygdala decreased under acute stress. Acute stress-induced increase of nicotine reward increased BDNF levels in the hippocampus. Moreover, the animals' exposure to the CPP apparatus without any drug administration increased the ratios of pCREB/tCREB and BDNF/β-actin in the targeted sites. In summary, the present study indicate that the alterations of the ratio of pCREB/CREB and also the level of BDNF in the hippocampus may be critical for enhancing nicotine reward under stress condition. The evidence from this study suggests the distinct roles of the hippocampus and the amygdala in mediating nicotine reward under stress.
['Ghasemzadeh|Zahra|Z|', 'Sardari|Maryam|M|', 'Javadi|Parastoo|P|', 'Rezayof|Ameneh|A|']
D000679:Amygdala D000818:Animals D019208:Brain-Derived Neurotrophic Factor D017362:Cyclic AMP Response Element-Binding Protein D004305:Dose-Response Relationship, Drug D015870:Gene Expression D006624:Hippocampus D007279:Injections, Subcutaneous D008297:Male D009538:Nicotine D051381:Rats D017208:Rats, Wistar D012201:Reward D015398:Signal Transduction D013315:Stress, Psychological
Amygdala Stress Hippocampus Nicotine reward Protein expression Rat(s)