title: Stress in Neonatal Rats with Different Maternal Care Backgrounds: Monoaminergic and Hormonal Responses.
abstract: The first 2 weeks of life in rats are known as the stress hyporesponsive period because stress responses in pups are diminished as compared to adult animals. However, it is considered a critical period in development in which infant rats are susceptible to environmental events, such as stressful stimuli and quality of maternal care received. These early life events have long-lasting effects, shaping a variety of outcomes, such as stress responsivity. This study investigated the effects of maternal care and sex differences on the response to an aversive stimulus in rat pups from high (HL) and low licking (LL) mothers. Plasma corticosterone, oxytocin, and central monoaminergic activity in 13-day-old rats submitted to cold stress were analyzed. Stress increased plasma corticosterone and marginally decreased hypothalamic dihydroxyphenylacetic acid/dopamine (DOPAC/DA) ratio. HL pups showed higher levels of plasma oxytocin than LL pups. The maternal effect was also detected in the hippocampus, in which 5-hydroxyindole-3-acetic acid/serotonin (5-HIAA/5-HT) ratio was increased in HL pups, independently of the sex and stress. Investigating the early life events is useful not only into understand the neurobiological and hormonal mechanisms underlying maternal and stressful influences on infant development into a healthy or psychopathological adult phenotype, but also to unveil the immediate outcomes on infancy.
authors.affiliation: Departamento de Fisiologia, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul (UFRGS), Sarmento Leite, 500, Porto Alegre, Rio Grande do Sul, 90050-170, Brazil, henriques.tp@gmail.com.
authors.forename: T P
authors.initials: TP
authors.lastname: Henriques
authors.forename: R E
authors.initials: RE
authors.lastname: Szawka
authors.forename: L A
authors.initials: LA
authors.lastname: Diehl
authors.forename: M A
authors.initials: MA
authors.lastname: de Souza
authors.forename: C N
authors.initials: CN
authors.lastname: Corrêa
authors.forename: B C C
authors.initials: BC
authors.lastname: Aranda
authors.forename: V
authors.initials: V
authors.lastname: Sebben
authors.forename: C R
authors.initials: CR
authors.lastname: Franci
authors.forename: J A
authors.initials: JA
authors.lastname: Anselmo-Franci
authors.forename: P P
authors.initials: PP
authors.lastname: Silveira
authors.forename: R M M
authors.initials: RM
authors.lastname: de Almeida