Endocrine and behavioural plasticity in response to juvenile stress in the semi-precocial rodent Octodon degus.
The present study in the South American rodent Octodon degus shows for the first time that the postnatal development of hypothalamic-pituitary-adrenal axis function in this semi-precocial species differs from that of altricial rodents, i.e. rats or mice, in several aspects. Our experiments revealed a particular pattern of hypothalamic-pituitary-adrenal axis activity during the first 3 weeks of life characterized by (i) a period of low plasma glucocorticoid concentrations, during which (ii) brief stress exposure (1 h parental separation) is able to elevate glucocorticoids significantly. In addition, (iii) repeated stress exposure (1 h parental separation daily) during the first 3 weeks of life resulted in females, but not in males, in an attenuated separation-induced increase of glucocorticoids, and a higher behavioural activity in both sexes at postnatal day 21. These data indicate that parental separation early in life acts as a 'strong' stressor in this species, which on the long run can alter endocrine stress response at the time of weaning in a sex-specific manner. These findings support the role of the hypothalamic-pituitary-adrenal axis as one of the key factors mediating the effects of early life stress on the neuronal network and behaviour in O. degus.
Gruss
M
M
Department of Zoology/Developmental Neurobiology, Institute of Biology, Otto von Guericke University Magdeburg, Brenneckestrasse 6, 39118 Magdeburg, Germany. michael.gruss@nat.uni-magdeburg.de
Westphal
S
S
Luley
C
C
Braun
K
K
D000208:Acute Disease; D000222:Adaptation, Physiological; D000223:Adaptation, Psychological; D000367:Age Factors; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D002908:Chronic Disease; D003345:Corticosterone / Q000097:blood*; D004195:Disease Models, Animal; D005220:Fathers; D005260:Female; D005938:Glucocorticoids / Q000097:blood; D006854:Hydrocortisone / Q000097:blood*; D007030:Hypothalamo-Hypophyseal System / Q000502:physiology / Q000503:physiopathology; D008297:Male; D009035:Mothers; D046329:Octodon / Q000502:physiology* / Q000523:psychology; D010913:Pituitary-Adrenal System / Q000502:physiology / Q000503:physiopathology; D012737:Sex Factors; D012931:Social Environment; D012934:Social Isolation / Q000523:psychology*; D013315:Stress, Psychological / Q000097:blood*
D005938:Glucocorticoids; D003345:Corticosterone; D006854:Hydrocortisone