RESUMEN
OBJECTIVES: Corticotropin releasing factor (CRF) plays a primary role in coordinating the neuroendocrine, autonomic, immune and behavioral responses to stress. CRF exerts its action through two major receptors, corticotropin-releasing factor 1 Receptor (CRF-R1) and corticotropin-releasing factor 2 receptor (CRF-R2). Using two types of chronic stress models, we investigated the changes of CRF-R1 mRNA and CRF-R2A mRNA expressions and CRF mRNA in the stress related brain circuit areas. METHODS: Male Sprague-Dawley rats were exposed to either immobilization stress or variable intermittent unpredictable stress for 10 days and then in situ hybridization histochemistry was used to quantify CRF expression in the brain. RESULTS: 1) CRF1 receptor mRNA expressions were decreased in bed nucleus stria terminalis (BNST) following stressors. 2) CRF2A receptor mRNA expressions were increased in lateral septum following stressors. 3) CRF mRNA expressions were increased in central nucleus of amygdala (CeA) and BNST. CONCLUSION: The increased CRF mRNA of CeA and BNST may be related with anxiety response in the repeated stress. Down-regulation of CRF-R1 mRNA expression in BNST may represent a compensatory adaptation to chronic stress and may be involved in the anxiety response, whereas up-regulation of CRF-R2A mRNA expression in lateral septum may represent an anxiety response or impaired learning but the functional meaning is uncertain.