Postpartum Corticosterone Administration Reduces Dendritic Complexity and Increases the Density of Mushroom Spines of Hippocampal <scp>CA</scp>3 Arbours in Dams
Bibliographic record
Abstract
Postpartum depression (PPD) affects approximately 15% of mothers after giving birth. A complete understanding of depression during the postpartum period has yet to be established, although disruptions in the hypothalamic-pituitary-adrenal axis and stress during the postpartum may be involved. To model these components in rats, we administered high corticosterone (CORT) postpartum, which increases immobility in the forced swim test (FST), and reduces maternal care, body weight and hippocampal cell proliferation in dams. The hippocampus is altered in response to chronic stress, exposure to high glucocorticoids and in major depression in humans. In the present study, we examined whether high CORT reduced dendritic complexity and spines in the CA3 region of the hippocampus. Additionally, housing complexity was manipulated so that dams and litters were housed either with tubes (complex) or without tubes (impoverished) to investigate the consequences of new animal care regulations. Dams received 40 mg/kg/day of CORT or oil starting on day 2 postpartum for 23 days. Maternal behaviours were assessed on postpartum days 2-8 and dams were tested using the FST on days 21 and 22. Dams were killed on day 24 and brains were processed for Golgi impregnation. Pyramidal cells in the CA3 subfield were traced using a camera lucida and analysed for branch points and dendritic complexity, as well as spine density and type on both basal and apical arbours. As previously established, high CORT postpartum reduced maternal care and increased immobility in the FST, which is a measure of depressive-like behaviour. High CORT postpartum reduced the complexity of basal arbours and increased mushroom spines on both apical and basal dendrites. Housing complexity had no effect on spines of CA3 pyramidal cells but modest effects on cell morphology. These data show that chronic high CORT in postpartum females alters hippocampal morphology and may provide insight regarding the neurobiological consequences of high stress or CORT during the postpartum period, as well as be relevant for postpartum stress or depression.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".