Brain oxytocin augments stress-induced long-lasting plasma adrenocorticotropic hormone elevation in rats.
Single stress induces long-lasting changes in the hypothalamo-pituitary--adrenal (HPA) axis of adult animals. Selective oxytocin (OXT) receptor antagonist was administrated into the cerebroventricle of male rats to test its influence on plasma adrenocorticotropic hormone (ACTH) responses induced by immobilization stress. The ACTH level is significantly higher than the control level (P<0.05) up to 6 days after single stress. Although the OXT antagonist did not change the plasma ACTH level at the end of single stress (P=0.59), the antagonist significantly decreased the ACTH concentration at the end of repeated (3 days) stress and 2 days after single stress (P<0.05) compared with controls. The results suggest that endogenous brain OXT enhances the long-lasting but not immediate HPA axis response to stress.
Nakashima
Toshihiro
T
Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, Japan. nakasima@ipc.kit.ac.jp
Noguchi
Tohru
T
Furukawa
Tomonori
T
Yamasaki
Michiyo
M
Makino
Shinya
S
Miyata
Seiji
S
Kiyohara
Toshikazu
T
D000324:Adrenocorticotropic Hormone / Q000097:blood* / Q000378:metabolism; D000818:Animals; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects / Q000378:metabolism*; D007276:Injections, Intraventricular; D008297:Male; D010121:Oxytocin / Q000031:analogs & derivatives* / Q000378:metabolism* / Q000494:pharmacology; D010913:Pituitary-Adrenal System / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D018045:Receptors, Oxytocin / Q000037:antagonists & inhibitors* / Q000378:metabolism; D013312:Stress, Physiological / Q000378:metabolism* / Q000503:physiopathology; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology*
D018045:Receptors, Oxytocin; D010121:Oxytocin; C042951:oxytocin,1-(beta-mercapto-(beta, beta-cyclopentamethylene)propionic acid)-Tyr(OMe)(2)-Orn(8)-; D000324:Adrenocorticotropic Hormone