title: Effects of denial of reward through maternal contact in the neonatal period on adult hypothalamic-pituitary-adrenal axis function in the rat.
abstract: Emotional behavioral traits associated with stress response are well documented to be affected by early life events. In the present work, we used a novel paradigm of neonatal experience, in which pups were trained in a T-maze and either received (RER rats) or were denied (DER) the reward of maternal contact, during postnatal days 10-13. We then evaluated stress coping and key factors controlling the function of the hypothalamic-pituitary-adrenal axis in adulthood. Adult male DER rats exposed to a single session of forced swim stress (FSS) showed increased immobility, while RER rats exhibited increased escape attempts. The corticosterone response following this stressor was higher although not prolonged in the DER rats. Their CRH mRNA levels in the PVN were increased up to 2h after the forced swim. However, basal levels of these hormones did not differ among groups. In addition, the DER neonatal experience induced an increase in hippocampal GR but a decrease in CRH-R1 immunopositive cells in the CA1 area of the hippocampus and the central amygdala. Overall, these data show a distinct stress response profile in the DER male rats, characterized by passive coping during the forced swim, increased hormonal response following stress, increased inhibitory control through GR and an indirect contribution of CRH-R1, the latter two factors resulting in a modified regulation of the response termination. It thus appears that DER rats have an enhanced potential for appropriate reactivity upon an incoming challenge, while maintaining in parallel an adequate control of the duration of their stress responses.
authors.affiliation: Laboratory of Biology-Biochemistry, Faculty of Nursing, School of Health Sciences, University of Athens, Papadiamantopoulou 123, GR-11527 Athens, Greece.
authors.forename: Anastasia
authors.initials: A
authors.lastname: Diamantopoulou
authors.forename: Androniki
authors.initials: A
authors.lastname: Raftogianni
authors.forename: Antonios
authors.initials: A
authors.lastname: Stamatakis
authors.forename: Melly S
authors.initials: MS
authors.lastname: Oitzl
authors.forename: Fotini
authors.initials: F
authors.lastname: Stylianopoulou
mesh_terms: D000223:Adaptation, Psychological; D000324:Adrenocorticotropic Hormone / Q000097:blood; D000679:Amygdala / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D003345:Corticosterone / Q000097:blood; D003346:Corticotropin-Releasing Hormone / Q000096:biosynthesis; D005260:Female; D006624:Hippocampus / Q000378:metabolism; D007030:Hypothalamo-Hypophyseal System / Q000378:metabolism*; D008297:Male; D008426:Maternal Deprivation; D010286:Paraventricular Hypothalamic Nucleus / Q000378:metabolism; D010913:Pituitary-Adrenal System / Q000378:metabolism*; D051381:Rats; D018019:Receptors, Corticotropin-Releasing Hormone / Q000378:metabolism; D011965:Receptors, Glucocorticoid / Q000378:metabolism; D012201:Reward; D013315:Stress, Psychological / Q000097:blood / Q000378:metabolism* / Q000523:psychology; D000099052:CRF Receptor, Type 1
chemical_list: D018019:Receptors, Corticotropin-Releasing Hormone; D011965:Receptors, Glucocorticoid; D000099052:CRF Receptor, Type 1; D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone; D003345:Corticosterone