Influence of chronic treatment with imipramine on mRNA levels in rat brain: elevation of glyceraldehyde-3-phosphate dehydrogenase levels.

The differential display method was used to identify the intrinsic factor that changes its mRNA expression level in rat brain after a 14-day oral administration of 20 mg/kg imipramine. The expression of a 180-bp band was markedly enhanced by imipramine. The results of sequencing and a data base search revealed that the isolated clone was glyceraldehyde-3-phosphate dehydrogenase (GAPDH) with a one-base difference. Enhancement of the expression by imipramine was observed in the amygdala. Quantitative PCR showed that imipramine treatment significantly elevated the GAPDH/beta-actin ratio in the cortex. These findings suggest that long-term treatment with imipramine stimulates GAPDH mRNA expression.