We consider our findings to contribute to the neurobiological evidence on the association between SP and brain structural changes in depression, which may be related with the pathophysiology and treatment of MDD.
Given the important role of the amygdaloid complex in the regulation of emotional behavior, we examined the mRNA levels of preprotachykinin A [PPT-A, a precursor of both SP and neurokinin A (NKA)] and 3H-SP binding sites in the amygdala of patients affected by bipolar disorder, major depression or schizophrenia as compared with matched control individuals.
In addition, substance P (SP), which is degraded by ACE, has been implicated in the pathogenesis of, and evaluated in the treatment for, major depressive disorder (MDD).