Year: 2012
Type: dissertation
Abstract: Once thought to occur only during specific periods of development, it is now \nclear that neurogenesis occurs in the rat hippocampus into adulthood. It is wellestablished \nthat stress during adulthood decreases the rate of neurogenesis, but during \nadolescence, the effects of stress are much less understood. I investigated the effect of \nshort-term or chronic stress during adolescence (daily lhr isolation and change of cage \npartner from postnatal day (PND) 30-32 or 30-45) on hippocampal neurogenesis. In \nexperiment 1, rats were administered Bromodeoxyuridine (BrdU) daily on PND 30-32, or \n46-48, to mark neurogenesis at the beginning of the stressor or after the stressor had \nceased, respectively. Neither short-term nor chronic stress had an effect on \nproliferation or survival (evidenced by BrdU and Doublecortin (Dcx) \nimmunohistochemistry respectively) of cells born at the beginning of the stress \nprocedure. Compared to controls, BrdU-labeling showed chronic stress significantly \nincreased proliferation of cells generated after the stressor had ceased, but survival of \nnew neurons was not supported (Dcx-Iabeling). However, it may be that BrdU injections \nare inherently stressful. In experiment 2, the stressor (described above) was applied in \nthe absence of BrdU injections. Ki67 (a marker of proliferation) showed that stress \ntransiently increased cell proliferation. Dcx-Iabeling showed that stress also increased \nneuron survival into adulthood. Labeling with OX.,.42 (a marker of macro phages) \nsuggested that the immune system plays a role in neurogenesis, as stress transiently \ndecreased the number of activated microglia in the hippocampus. It can be concluded \nthat in the adolescent male rat, chronic mild stress increases neurogenesis.
Author: Catherine Thomas
Language: English
Subfield: Developmental Neuroscience
Field: Neuroscience
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W2939192133