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Transient and persistent behavioral and molecular changes in primiparous female Wistar rats
Author(s) -
Naik Roshan R.,
Jong Trynke R.
Publication year - 2017
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/ejn.13411
Subject(s) - stria terminalis , medicine , oxytocin , endocrinology , vasopressin , oxytocin receptor , weaning , estrous cycle , offspring , biology , septal nuclei , hypothalamus , psychology , amygdala , pregnancy , genetics
Motherhood brings about a multitude of behavioral and physiological changes in dams and some of these persist until after weaning. We studied behavioral changes associated with reproductive experience at lactating day ( LD )8, at weaning ( LD 21), and 28 days post‐weaning ( PW 28) compared to nulliparous ( NP ) females. Furthermore, in another cohort of animals, we quantified mRNA expression of five target genes known to be associated with maternal experience: arginin‐vasopressin( Avp ) and its 1A receptor( Avpr1a) , oxytocin(Oxt) and its receptor( Oxtr), and corticotropin‐releasing hormone( Crh ) in three key maternal region: the medial preoptic area ( MPOA ), bed nucleus of the stria terminalis ( BNST ) and paraventricular hypothalamic nucleus( PVN ). Although dams were slightly less anxious than NP at LD 8, this effect did not persist at LD 21 and PW 28. No differences in social preference were found between the four groups. In the maternal responsiveness test ( MRT ), LD 8 and LD 21 dams were immediately responsive to pups whereas NP largely avoided the pups throughout 12‐day period. PW 28 females were significantly more responsive to pups than NP females, but less than LD 8 and LD 21 females. The mRNA expression of Avp in the PVN , Avpr1a in the BNST and Oxtr in the MPOA and BNST was increased, whereas mRNA expression of Avpr1a was reduced in the PVN , at LD 8 compared to NP . Although Oxtr in the BNST and Avp in the PVN were still somewhat (non‐significantly) increased at LD 21, all levels of gene expression had normalized at PW 28. Our results emphasize the transient nature of these behavioral and molecular adaptations, except for a persistent up‐regulation of maternal responsiveness.