Effects of maternal and sibling deprivation on basal and stress induced hypothalamic-pituitary-adrenal components in the infant rat

• Published in: Neuroscience letters Vol. 192; no. 1; pp. 49 - 52
• Main Authors: Avishai-Eliner, Sarit, Yi, Su-Jin, Newth, Christopher J.L., Baram, Tallie Z.
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier Ireland Ltd 02.06.1995; Elsevier
• Subjects: Adrenal Glands - metabolism; Animals; Animals, Newborn; Behavioral psychophysiology; Biological and medical sciences; Corticosterone; Corticosterone - biosynthesis; Corticosterone - blood; Corticotropin releasing hormone; Development; Female; Fundamental and applied biological sciences. Psychology; Hormones and behavior; Hypothalamic-pituitary-adrenal; Hypothalamo-Hypophyseal System - metabolism; Infant rat; Maternal Deprivation; Messenger RNA; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Rats; Rats, Sprague-Dawley; Sibling Relations; Stress; Stress, Physiological - metabolism; Time Factors; Corticotropin releasing hormone; Messenger RNA; Corticosterone; Development; Maternal deprivation; Hypothalamic-pituitary-adrenal; Stress; Infant rat; Deprivation; Rat; Hypothalamohypophysoadrenal axis; Rodentia; Central nervous system; ACTH-RH; Hypothalamus; Glucocorticoid; Young animal; Endocrine secretion; Hypothalamic hormone; Vertebrata; Mammalia; Mother young relation; Animal; Adrenal hormone; Hormone releasing factor; Brain (vertebrata); Hormonal receptor
• ISSN: 0304-3940; 1872-7972
• DOI: 10.1016/0304-3940(95)11606-W

Prolonged maternal deprivation during early infancy increases basal- and stress-induced corticosterone (CORT) levels, but the underlying mechanism is not clear. In general, stressors activate the hypothalamic-pituitary-adrenal (HPA) axis, with secretion and compensatory synthesis of hypothalamic corticotropin-releasing hormone (CRH). In the infant rat, we have demonstrated that maximally tolerated acute cold stress induced a robust elevation of plasma CORT throughout the first 2 postnatal weeks. However CRH messenger RNA (CRH-mRNA) abundance 4 h subsequent to cold stress was enhanced only in rats aged 9 days or older. This suggests a developmental regulation of the CRH component of the HPA-response to this stressor. The present study examined whether increased basal and cold stress-induced CORT levels after 24 h of maternal deprivation were due to enhanced CRH-mRNA abundance in the hypothalamic paraventricular nucleus (PVN). CRH-mRNA abundance, and basal- and cold-induced plasma CORT levels were measured in maternally deprived 6 and 9-day-old pups compared to non-deprived controls. Maternal deprivation increased basal and cold-induced CORT levels on both 6 and 9-day-old rats. CRH-mRNA abundance in the PVN of deprived rats did not differ from that in non-deprived rats. Our results indicate that the enhanced basal and stress-induced plasma CORT observed after 24 h maternal deprivation is not due to increased CRH-mRNA abundance in the PVN.