Effect Of Voluntary Training On Glucocorticoid Responsiveness To Restraint Stress In Sprague-Dawley Rats
Notice bibliographique
Résumé
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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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,001 | 0,000 |
| Méta-épidémiologie (sens large) | 0,001 | 0,000 |
| Bibliométrie | 0,001 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».