Neuroendocrine and behavioral effects of CRH blockade and stress in male rats.
Our previous data have shown that restraint (RT), a mild nonpainful stressor, acutely impairs nonsocial and social behavior in male rats. Corticotropin-releasing hormone (CRH) is a regulator of these behavioral responses. To evaluate whether CRH mediates the neuroendocrine and behavioral alterations present 24 h after restraint stress, we administered the CRH antagonist alpha-helical CRH(9-41) (alpha-hCRH) intracerebroventricularly to male rats and we compared its effects with those of saline. Twenty-four hours after treatment, nonsocial behaviors were significantly decreased by alpha-hCRH, this effect being independent of RT. Among social behaviors, only introductory activity showed significant differences as a result of both RT and alpha-hCRH. The concentrations of ACTH in the plasma and those of beta-endorphin in the anterior and neurointermediate lobes of the pituitary were affected by alpha-hCRH treatment. The effect on ACTH was simply related to the administration of the alpha-hCRH, while for beta-endorphin, significant interactions between alpha-hCRH and RT were found. On the whole, these results point to the role played by CRH in the control of neuronal mechanisms involved in the stress-induced effects.
Aloisi
A M
AM
Institute of Human Physiology, University of Siena, Italy. Aloisi@unisi.it
Bianchi
M
M
Lupo
C
C
Sacerdote
P
P
Farabollini
F
F
D000324:Adrenocorticotropic Hormone / Q000097:blood / Q000502:physiology; D000704:Analysis of Variance; D000818:Animals; D001007:Anxiety / Q000139:chemically induced / Q000503:physiopathology; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology*; D003346:Corticotropin-Releasing Hormone / Q000037:antagonists & inhibitors / Q000494:pharmacology / Q000502:physiology*; D005106:Exploratory Behavior / Q000187:drug effects; D006727:Hormone Antagonists / Q000494:pharmacology; D008297:Male; D010902:Pituitary Gland / Q000737:chemistry / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D012149:Restraint, Physical / Q000009:adverse effects; D012919:Social Behavior; D013315:Stress, Psychological / Q000139:chemically induced / Q000209:etiology / Q000503:physiopathology*; D001615:beta-Endorphin / Q000032:analysis / Q000187:drug effects
D006727:Hormone Antagonists; C069206:alpha helical corticotropin-releasing hormone; D001615:beta-Endorphin; D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone