The central role of corticotrophin-releasing factor (CRF-41) in psychological stress in rats.
1. We investigated the central role of corticotrophin-releasing factor (CRF-41) in psychological stress-induced responses, including cardiovascular, thermoregulatory and locomotive activity in free-moving rats. 2. Psychological stress was induced by cage-switch stress. After rats were placed in the novel environment, blood pressure, heart rate, body temperature and locomotive activity significantly increased. The intracerebroventricular (I.C.V.) injection of alpha-helical CRF(9-41), a CRF-41 receptor antagonist, significantly attenuated the stress-induced hypertension, tachycardia, hyperthermia and increase in locomotive activity. However, in unstressed rats, the I.C.V. injection of alpha-helical CRF(9-41) had no effect on physiological parameters measured in this study. 3. In unstressed rats, the I.C.V. injection of CRF-41 (1 microgram and 10 micrograms) increased blood pressure, heart rate, body temperature and locomotive activity in a dose-dependent manner. The changes in these responses were quite similar to those observed during cage-switch stress. 4. The results suggest that central CRF-41 plays an important role in psychological stress-induced hypertension, hyperthermia, tachycardia and increase in locomotive activity. However, it is likely that central CRF-41 does not contribute to normal cardiovascular and body temperature regulation when rats are free from stress.
Morimoto
A
A
Department of Physiology, Yamaguchi University School of Medicine, Japan.
Nakamori
T
T
Morimoto
K
K
Tan
N
N
Murakami
N
N
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D001833:Body Temperature Regulation / Q000187:drug effects; D002319:Cardiovascular System / Q000503:physiopathology*; D003346:Corticotropin-Releasing Hormone / Q000037:antagonists & inhibitors / Q000494:pharmacology / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D007276:Injections, Intraventricular; D008124:Locomotion / Q000187:drug effects; D008297:Male; D010446:Peptide Fragments / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D013315:Stress, Psychological / Q000378:metabolism*
D010446:Peptide Fragments; D003346:Corticotropin-Releasing Hormone; C045089:corticotropin releasing hormone (9-41)