Rapid and Widespread Effects of 17β-Estradiol on Intracellular Signaling in the Male Songbird Brain: A Seasonal Comparison
Bibliographic record
Abstract
Across vertebrate species, 17β-estradiol (E(2)) acts on the brain via both genomic and nongenomic mechanisms to influence neuronal physiology and behavior. Nongenomic E(2) signaling is typically initiated by membrane-associated estrogen receptors that modulate intracellular signaling cascades, including rapid phosphorylation of ERK. Phosphorylated ERK (pERK) can, in turn, rapidly phosphorylate tyrosine hydroxylase (TH) and cAMP response element-binding protein (CREB). Recent data suggest that the rapid effects of E(2) on mouse aggressive behavior are more prominent during short photoperiods (winter) and that acute aromatase inhibition reduces songbird aggression in winter only. To date, seasonal plasticity in the rapid effects of E(2) on intracellular signaling has not been investigated. Here, we compared the effects of acute (15 min) E(2) treatment on pERK, pTH, and pCREB immunoreactivity in male song sparrows (Melospiza melodia) pretreated with the aromatase inhibitor fadrozole during the breeding and nonbreeding seasons. We examined immunoreactivity in 14 brain regions including portions of the song control system, social behavior network, and the hippocampus (Hp). In both seasons, E(2) significantly decreased pERK in nucleus taeniae of the amygdala, pTH in ventromedial hypothalamus, and pCREB in mesencephalic central gray, robust nucleus of the arcopallium, and caudomedial nidopallium. However, several effects were critically dependent upon season. E(2) decreased pERK in caudomedial nidopallium in the breeding season only and decreased pCREB in the medial preoptic nucleus in the nonbreeding season only. Remarkably, E(2) decreased pERK in Hp in the breeding season but increased pERK in Hp in the nonbreeding season. Together, these data demonstrate that E(2) has rapid effects on intracellular signaling in multiple regions of the male brain and also demonstrate that rapid effects of E(2) can be profoundly different across the seasons.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".