Regulation of the adrenocorticotrophin response to stress by the central nucleus of the amygdala in rats depends upon the nature of the stressor.
The regulatory role of the medial (CeM) or the lateral (CeL) part of the central nucleus of the amygdala on the hypothalamo-pituitary-adrenal axis response to stress was investigated in male rats. Basal and restraint- or lipopolysacharride (LPS)-induced plasma adrenocorticotrophic hormone (ACTH) levels were measured 7 days after sham operation or lesion of the CeM or CeL. CeM or CeL lesion did not change basal ACTH concentrations. In control rats, restraint or LPS injection induced a robust increase in ACTH secretion. CeL lesion did not modify the stress-induced increment in ACTH release. CeM lesion significantly decreased the ACTH response to restraint and potentiated the ACTH response to LPS injection. Our findings demonstrate that the CeM exerts complex influences on the corticotrophic response to stress, being either stimulatory or inhibitory, depending on the nature of the stressor.
Marcilhac
A
A
Neuroendocrinological Laboratory, INSERM U 297, University of Medicine, Marseille, France.
Siaud
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P
D000324:Adrenocorticotropic Hormone / Q000378:metabolism*; D000679:Amygdala / Q000503:physiopathology*; D000818:Animals; D008070:Lipopolysaccharides / Q000008:administration & dosage; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012149:Restraint, Physical; D013312:Stress, Physiological / Q000209:etiology / Q000503:physiopathology*
D008070:Lipopolysaccharides; D000324:Adrenocorticotropic Hormone