Studies of a brain polypeptide functioning as a putative endogenous ligand to benzodiazepine recognition sites in rats selectively bred for alcohol related behavior.

The brain content of Diazepam Binding Inhibitor (DBI), its cell location and that of its specific mRNA were studied immunohistochemically and by in situ hybridization. Various strains of rats were genetically selected for their alcohol tolerance and the above mentioned brain parameters were studied before and after chronic ethanol consumption. The DBI like immunoreactivity (DBI-LI) was found to be located in selected neuronal population and in non-neuronal cells. The DBI-mRNA was located in brain areas where DBI is abundant. It was immunochemically determined that the DBI content was increased in cerebellum and in hypothalamus of alcohol preferring rats after chronic ethanol consumption. DBI content was compared in the cerebellum of rats genetically selected for different alcohol sensitivity and it was significantly higher on the ethanol sensitive (ANT) rat strain.