title: Calorie restriction and corticosterone elevation during lactation can each modulate adult male fear and anxiety-like behaviour.
abstract: Early life events, such as calorie restriction (CR) and elevated glucocorticoids, can calibrate the lifelong behavioural and physiological profile of an individual. Stress reactivity in adulthood is particularly sensitive to early life events; however, the consequence to fear and anxiety-like behaviour is less clear. Consequently, the current study sought to examine the effects of post-natal CR and glucocorticoid elevation, long considered powerful programming stimuli, on the subsequent fear and anxiety behaviour of the adult offspring. Rat dams received either corticosterone (200 μg/ml) supplementation in drinking water (CORT) or a 25% CR from post-natal day (PND) 1 to 11. Responses to the elevated plus maze (EPM), open field and a predator odour (TMT; 2,5-dihydro-2,4,5-trimethylthiazoline) were characterised in the adult male offspring. Both treatment conditions resulted in enhanced fear responses to TMT, characterised by heightened risk assessment and increased avoidance of TMT. CORT nursed offspring further demonstrated an anxiogenic profile in the open field. Basal hypothalamic-pituitary-adrenal function was unchanged in CORT adult offspring, whilst corticosterone concentration was elevated by post-natal CR. CR and CORT treated dams both exhibited greater anxiety-like behaviour in the EPM. A modest and temporary enhancement of maternal care was observed in CR and CORT treated dams, with CR dams further exhibiting rapid pup retrieval latencies. The results indicate enhanced emotionality in the adult male progeny of dams exposed to CR and corticosterone supplementation during the post-natal period. The modest enhancement of maternal care observed by both treatments is unlikely to have influenced the behavioural profile of the offspring.
authors.affiliation: School of Health Sciences, College of Science Engineering & Health, RMIT University, Australia. Electronic address: antonina.govic@rmit.edu.au.
authors.forename: Antonina
authors.initials: A
authors.lastname: Govic
authors.affiliation: School of Psychological Science, La Trobe University, Bundoora, VIC, Australia.
authors.forename: Veronica
authors.initials: V
authors.lastname: Bell
authors.affiliation: School of Health Sciences, College of Science Engineering & Health, RMIT University, Australia.
authors.forename: Anil
authors.initials: A
authors.lastname: Samuel
authors.affiliation: School of Health Sciences, College of Science Engineering & Health, RMIT University, Australia.
authors.forename: Jim
authors.initials: J
authors.lastname: Penman
authors.affiliation: School of Health Sciences, College of Science Engineering & Health, RMIT University, Australia; School of Psychological Science, La Trobe University, Bundoora, VIC, Australia.
authors.forename: Antonio G
authors.initials: AG
authors.lastname: Paolini
mesh_terms: D000375:Aging; D000818:Animals; D000833:Animals, Suckling; D001007:Anxiety / Q000209:etiology; D001522:Behavior, Animal / Q000187:drug effects*; D031204:Caloric Restriction / Q000009:adverse effects / Q000523:psychology*; D003345:Corticosterone / Q000378:metabolism / Q000494:pharmacology*; D005106:Exploratory Behavior / Q000187:drug effects / Q000502:physiology; D005239:Fear / Q000187:drug effects; D005260:Female; D005938:Glucocorticoids / Q000494:pharmacology; D007774:Lactation; D008297:Male; D051381:Rats; D017208:Rats, Wistar
chemical_list: D005938:Glucocorticoids; D003345:Corticosterone
keywords: Anxiety-like behaviour; Calorie restriction; Early stress; Fear behaviour; Maternal behaviour; Maternal corticosterone; Maternal programming; Post-natal period