Corticotropin-releasing factor (CRF), but not corticosterone, increases basolateral amygdala CRF-binding protein.
Corticotropin-releasing factor (CRF) is a key mediator of the behavioral, autonomic, and endocrine responses to stress. CRF binds two receptors and a CRF-binding protein (CRF-BP), which may inactivate or modulate the actions of CRF at its receptors. The amygdala is an important anatomical substrate for CRF and contains CRF, its receptors, and CRF-BP. Our previous studies demonstrated that acute stress increases basolateral amygdala (BLA) CRF-BP mRNA. However, factors that may be responsible for this increase remain unclear. Both CRF and corticosterone are released during stress and are known to increase CRF-BP in vitro. However, the effects of these agents in vivo on brain CRF-BP have not been studied. Therefore, we examined the effects of CRF and corticosterone administration on BLA CRF-BP mRNA in rats. The findings demonstrate that intracerebroventricular CRF (5 microg) significantly increases BLA CRF-BP mRNA 9 h post-infusion, a time point consistent with that observed for the effects of acute stress-induced increases in CRF-BP. In contrast, injection of corticosterone at a dose mimicking acute stress (6.5 mg/kg sc) failed to increase BLA CRF-BP mRNA 9 h post-injection. Surprisingly, two different CRF antagonists failed to block CRF-induced increases in CRF-BP mRNA. These results suggest that CRF, but not corticosterone, may be responsible for stress-induced increases in BLA CRF-BP gene expression. Furthermore, this effect appears to be mediated by mechanisms other than the identified CRF receptors.
Herringa
Ryan J
RJ
Wisconsin Psychiatric Institute and Clinics, 6001 Research Park Boulevard, Madison, WI 53719-1176, USA.
Mackenrodt
Daniel B
DB
Barlow
Jon D
JD
Roseboom
Patrick H
PH
Nanda
Steven A
SA
Kalin
Ned H
NH
D000679:Amygdala / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D003345:Corticosterone / Q000097:blood* / Q000494:pharmacology; D003346:Corticotropin-Releasing Hormone / Q000378:metabolism* / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005786:Gene Expression Regulation / Q000187:drug effects / Q000235:genetics; D008297:Male; D011485:Protein Binding / Q000187:drug effects / Q000235:genetics; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D018019:Receptors, Corticotropin-Releasing Hormone / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D013312:Stress, Physiological / Q000097:blood* / Q000235:genetics / Q000503:physiopathology; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology; D000099052:CRF Receptor, Type 1
C101531:CRF receptor type 2; D002352:Carrier Proteins; D012333:RNA, Messenger; D018019:Receptors, Corticotropin-Releasing Hormone; C067133:corticotropin releasing factor-binding protein; D000099052:CRF Receptor, Type 1; D003346:Corticotropin-Releasing Hormone; D003345:Corticosterone