Effect Of Voluntary Training On Glucocorticoid Responsiveness To Restraint Stress In Sprague-Dawley Rats
Bibliographic record
Abstract
Exercise training is a potent activator of the hypothalamo-pituitary adrenal (HPA) axis. In rodents, forced training reduces hippocampus glucocorticoid (GC) receptor expression and may cause chronic elevations in basal GC levels. The effects of voluntary training are less clear but have been shown to cause reductions in hippocampal corticosteroid receptor binding and an exaggerated GC response to a novel stress. PURPOSE In the present study, we examined the effects of voluntary training on the diurnal HPA-axis rhythm as well as the responsiveness to, and recovery from restraint stress. METHODS Male, Sprague-Dawley rats were divided into training (T) and sedentary (S) groups (n=8 in each). For 4 weeks, the T rats were individually housed in cages with 24h access to running wheels, while the S rats were individually housed in standard cages. Both groups had free access to food and water. Diurnal plasma GC levels were measured weekly (0800, 1900, 0100h) followed by a standardized restraint stress protocol at the end of 4 weeks. For this, plasma GCs were measured intermittently during 20 min of tube restraint and 95 min of recovery. RESULTS The running distance in T increased from 1997±274m/day (X ± SEM) at week 1 to 8960±146m/day at week 4 (p < 0.001). No significant differences were observed in adrenal gland size between the two groups. A significant week by group interaction was found for diurnal plasma GC concentrations (p < 0.05). In week one, GC levels were higher in T than in S rats (T = 229±27 ng/ml vs S = 122±14 ng/ml, P=0.002 for data collapsed over time of day) but progressively decreased throughout the training protocol to reach similar values by week 4 (T = 147±17 ng/ml vs S = 112±17 ng/ml, P=NS). During restraint, GC values increased similarly in both groups (67±27 vs 43±11ng/ml at t=0 to 521±57 vs 499±29 ng/ml at t=20 min in T vs S, respectively, P=NS). During recovery, values were also similar between groups and reached basal levels by 80 min (71±15 vs, 53±11 in T vs S, respectively, P= NS). CONCLUSION Voluntary training in rats causes an initial up-regulation in diurnal GC levels, which are restored to normal by 4 weeks of training. Moreover, at 4 weeks, T rats have a normal response and recovery from restraint stress. These findings indicate that voluntary endurance training is associated with an initial hyperactivation of diurnal HPA activity, which is restored to basal by 4 weeks of training. In addition, 4 weeks of training is associated with normal response and recovery to a non-exercise stressor.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 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) | 0.001 | 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".