Decreased Amygdala CRF-Binding Protein mRNA in Post-Mortem Tissue from Male but not Female Bipolar and Schizophrenic Subjects

Abstract

Stressful life events are commonly associated with the onset and maintenance of psychopathology and much research has focused on the role of the corticotropin-releasing factor (CRF) system in mediating psychopathology. Since CRF serves to integrate the stress response, it is possible that the CRF system plays a role as a neurochemical linkage between stress and psychopathology. CRF-binding protein (CRF-BP) is thought to modulate CRF activity by decreasing its actions. Therefore, in some psychopathological states, alterations in CRF-BP function may contribute to dysregulation of the CRF system. Since the amygdala CRF system mediates stress- and anxiety-related behaviors and alterations in amygdala function are associated with psychopathology, we examined amygdala CRF-BP gene expression in post-mortem brains from subjects with major depression, bipolar disorder, and schizophrenia as well as in controls. In addition to characterizing the anatomic distribution of CRF-BP mRNA in the human amygdala and medial temporal lobe region, we found a significant decrease in CRF-BP mRNA levels in the basolateral amygdala of male bipolar and male schizophrenic subjects and the lateral amygdala of male bipolar subjects. These results raise the possibility that men with decreased amygdala CRF-BP may be more vulnerable to the effects of stress exposure on the etiology or maintenance of bipolar disorder or schizophrenia.