[Abstract Title]. - Society for Neuroscience

Title: Maternal deprivation affects hippocampal neurogenesis in a sex-dependent manner
Authors: *C. OOMEN, C. E. NEVES GIRARDI, E. C. VERBEEK, R. CAHYADI, H.
KRUGERS, M. JOËLS, P. J. LUCASSEN;
SILS-Center for neuroscience, Univ. Amsterdam, Amsterdam, Netherlands
Abstract: Hippocampal structural and functional plasticity are highly susceptible to stress and
stress hormones. A striking example of structural plasticity in the hippocampus is adult
neurogenesis. Unlike other brain areas, the dentate gyrus of the hippocampus continues to
generate new neurons into adulthood. Adult neurogenesis is influenced by various environmental
factors and is inhibited by acute and chronic stress and stress hormones. This could potentially
affect hippocampal functioning.
The impact of stress is generally more pronounced when applied early in life. There is evidence
that several properties of the hypothalamic-pituitary-adrenal axis can be life-long altered due to
early life experiences. In rat pups, maternal behaviour ensures a “stress-hyporesponsive” period
between postnatal day (PND) 3 and 14. This period coincides with postnatal development of the
hippocampal dentate gyrus and with maximal levels of neurogenesis. We hypothesized that
maternal deprivation at the beginning of this period will influence neurogenesis and alters the
structural make up of the adult hippocampus and that this could potentially influence network
properties later in life.
To investigate this, we subjected rat pups to 24 hours of maternal deprivation at PND 3 and, at
that time, labelled dividing cells by injecting BrdU (bromodeoxyuridine). Changes in maternal
care were monitored during the experimental procedure. At PND4 we studied the acute effect of
maternal deprivation on proliferation and at PND21 we analysed the different phases of
neurogenesis by quantifying cell-survival, proliferation, neuronal differentiation and the number
of astrocytes.
We found no differences between groups in cell survival or proliferation rate at PND21. Analysis
of the population of immature neurons (doublecortin-positive cells) revealed an increase in
males, but a decrease in females due to maternal deprivation. However, the volume of granular
cell layer was unchanged due to experimental procedure. Maternal care was increased after the
deprivation day, but this increase was similar for male and female pups. We are presently
studying whether the effect on immature neurons is transient or persisting into adulthood and
what the functional consequences are for long-term potentiation in the dentate gyrus.
We conclude that maternal deprivation induces sex-dependent differences in adult neurogenesis,
without affecting newborn cell survival or volume of the granular cell layer. This points to sexdependent
changes in maturation speed of young neurons, or a difference in cell-fate
determination following exposure to early life stress.
Disclosures: C. Oomen, None; C.E. Neves Girardi, None; E.C. Verbeek, None; R. Cahyadi,
None; H. Krugers, None; M. Joëls, None; P.J. Lucassen, None.
Poster