Excessive alcohol consumption is blocked by glial cell line-derived neurotrophic factor

We previously found that activation of the glial cell line-derived neurotrophic factor (GDNF) pathway in the ventral tegmental area (VTA) reduces moderate alcohol (ethanol) intake in a rat operant self-administration paradigm. Here, we set out to assess the effect of GDNF in the VTA on excessive voluntary consumption of ethanol. Long-Evans rats were trained to drink large quantities of a 20% ethanol solution in an intermittent-access two-bottle choice drinking paradigm. The rats were given three 24-h sessions per week, and GDNF's actions were measured when rats achieved a baseline of ethanol consumption of 5.5 g/kg/24 h. We found that microinjection of GDNF into the VTA 10 min before the beginning of an ethanol-drinking session significantly reduced ethanol intake and preference, but did not affect total fluid intake. We further show that GDNF greatly decreased both the first bout of excessive ethanol intake at the beginning of the session, and the later consummatory activity occurring during the dark cycle. These data suggest that GDNF is a rapid and long-lasting inhibitor of "binge-like" ethanol consumption. (C) 2009 Elsevier Inc. All rights reserved.