Infusion of brain‐derived neurotrophic factor into the ventral tegmental area switches the substrates mediating ethanol motivation

Recent work has shown that infusion of brain‐derived neurotrophic factor ( BDNF ) into the ventral tegmental area ( VTA ) promotes a switch in the mechanisms mediating morphine motivation, from a dopamine‐independent to a dopamine‐dependent pathway. Here we showed that a single infusion of intra‐ VTA BDNF also promoted a switch in the mechanisms mediating ethanol motivation, from a dopamine‐dependent to a dopamine‐independent pathway (exactly opposite to that seen with morphine). We suggest that intra‐ VTA BDNF , via its actions on T rk B receptors, precipitates a switch similar to that which occurs naturally when mice transit from a drug‐naive, non‐deprived state to a drug‐deprived state. The opposite switching of the mechanisms underlying morphine and ethanol motivation by BDNF in previously non‐deprived animals is consistent with their proposed actions on VTA GABA A receptors.