Differential regulation of variant glucocorticoid receptor mRNAs in the rat hippocampus by the antidepressant fluoxetine

Adult rats were given antidepressant drugs orally. Fluoxetine, but not moclobemide, venlafaxine, tianeptine or desipramine, increased total glucocorticoid receptor (GR) mRNA in the hippocampus after 4 weeks. Further examination revealed that GR mRNA containing the brain-specific exon 17 was increased across all hippocampal subregions. In contrast, expression of the major exon 110 and another brain-specific exon 15-containing GR mRNAs were unchanged. Tissue-specific first exon usage may contribute to the differential regulation of GR by fluoxetine in brain subregions.