Brain region-dependent changes in the expression of endocannabinoid-metabolizing enzymes in rats following antidepressant drugs.

The endocannabinoid (eCB) system plays a role in the pathophysiology of depression. The aim of this study was to investigate the expression of the eCB synthesizing enzymes (N-acyl phosphatidylethanolamine phospholipase D (NAPE-PLD) and diacylglycerol lipase alpha (DAGLalpha)) and eCB degrading enzymes (fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL)) after acute or chronic administration of antidepressant drugs (imipramine (IMI, 15 mg/kg), escitalopram (ESC, 10 mg/kg) and tianeptine (TIA, 10 mg/kg)). eCB metabolizing enzymes were altered in drug-dependent and brain region-specific fashion. After IMI treatment a reduction was noted in the expression of FAAH protein in the dorsal striatum, MAGL in the frontal cortex and DAGLalpha in the cerebellum. On the other hand, ESC treatment provoked an increase in the MAGL expression in the prefrontal cortex or NAPE-PLD and in DAGLalpha in the hippocampus and dorsal striatum, while reducing the FAAH expression in the dorsal striatum. TIA administration increased the levels of all enzymes in the prefrontal cortex as well as elevated DAGLalpha expression in the frontal cortex and dorsal striatum. In conclusion, our results indicate that changes in the eCBs levels after antidepressant drug treatment were related to the expression of their metabolizing enzymes.