Effects of Single Administration of Bupropion on Carboxypeptidase E Activity in Structures of Rat Brain.

Depression is associated with changes in the levels of some neurotransmitters in various brain structures. Being the key enzyme of peptide processing, carboxypeptidase E regulates their levels in various structures of the nervous system. Single injection of bupropion induced long-lasting changes in carboxypeptidase E activity in all brain structures. The decrease in enzyme activity observed in 12 and 24 h after bupropion injection confirmed the inhibiting effect of the drug on the hypothalamic-pituitary-adrenal axis. Activation of the enzyme in the medulla oblongata, hypothalamus, and hippocampus observed in 72 h after bupropion administration probably leads to enhanced synthesis and secretion of regulatory peptides (reduced during stress and depression) and stimulation of neurogenesis. Changes in enzyme activity can be a mechanism regulating the level of bioactive peptides involved in the pathogenesis of depression.