Contingent and non-contingent recreational-like exposure to ethanol alters BDNF expression and signaling in the cortico-accumbal network differently

• DOI: 10.1007/s00213-016-4358-y
• Publication Date: 2016-07-01T19:59:26Z
• Authors: Alessandro Orrù; Lucia Caffino; Federico Moro; Chiara Cassina; Giuseppe Giannotti; Angelo Di Clemente; Fabio Fumagalli; Luigi Cervo
• Keywords: Self-administration; Extended amygdala

Although brain-derived neurotrophic factor (BDNF) is part of a homeostatic pathway involved in the development of alcohol dependence, it is not clear whether this is also true after recreational ethanol consumption.We examined BDNF expression and signaling in the cortico-striatal network immediately and 24 h after either a single intravenous (i.v.) ethanol operant self-administration session or the last of 14 sessions.To compare contingent and non-contingent ethanol exposure, we incorporated the "yoked control-operant paradigm" in which rats actively taking ethanol (S-Et) were paired with two yoked controls receiving passive infusions of ethanol (Y-Et) or saline.A single ethanol exposure transiently reduced BDNF mRNA levels in the medial prefrontal cortex (mPFC) of Y-Et. Immediately after the last of 14 sessions, mRNA and mature BDNF protein levels (mBDNF) were reduced in the mPFC in both S-Et and Y-Et while mBDNF expression was raised in the nucleus accumbens (NAc), suggesting enhanced anterograde transport from the mPFC. Conversely, 24 h later mBDNF expression and signaling were raised in the mPFC and NAc of S-Et rats but reduced in the NAc of Y-Et rats, with concomitant reduction of downstream signaling pathways.Our findings indicate that recreational-like i.v. doses of ethanol promote early changes in neurotrophin expression, depending on the length and modality of administration, the brain region investigated, and the presence of the drug. A rapid intervention targeting the BDNF system might be useful to prevent escalation to alcohol abuse.