Gene expression changes in single dentate granule neurons after adrenalectomy of rats

Removal of corticosterone by adrenalectomy induces apoptosis 3 days later, in some, but not all, rat dentate granule cells. We hypothesized that individual dentate cells trigger specific gene expression profiles that partly determine their apoptosis susceptibility. RNA was collected from physiologically characterized granule cells at 2 or 3 days after adrenalectomy or sham operation, and linearly amplified. The amplified RNA was hybridized to cDNA clones of: (1) candidate genes earlier identified after adrenalectomy in whole hippocampi with SAGE; and (2) genes encoding growth factors and their receptors. We observed that based on the entire expression profile, cells relatively resistant to apoptosis 3 days after adrenalectomy clustered together with one-third of cells 2 days after adrenalectomy. Within the group of ADX cells, a limited number of transcript ratios were found to correlate-positively or negatively-with a known risk factor for apoptosis, calcium influx. The overall analysis of physiological properties and multiple gene expression in single cells can narrow down the number of critical genes involved in apoptosis identified with large scale gene screening methods and allows a first impression of their role as being a potential risk factor or neuroprotective.