Sex Differences in Blood Pressure Regulation During Ischemic Isometric Exercise: The Role of the β‐Adrenergic Receptors
Notice bibliographique
Résumé
Sex differences have been reported in the respective contribution of cardiac output (Q̇) and vascular constriction to the pressor response to isometric handgrip exercise (IHE). Differently from men, the majority of the blood pressure (BP) response to IHE in young women is due to elevated Q̇ rather than elevations in total peripheral resistance (TPR). The underlying mechanisms for these differences are unknown, but previous data suggest that the β‐adrenergic receptors offset α‐adrenergic vasoconstriction in young women under resting condition. Whether this could be extended to an exercise condition remains to be determined. Given this, the aim of the present study was to investigate whether the β‐adrenergic receptors play a pivotal role in sex‐related differences in the BP regulation during ischemic IHE. Ten men (21 ± 0.6 years) and 9 women (23 ± 1.3 years) healthy and physically active volunteers were recruited. All women were non‐oral contraceptives users and performed experiments in the early follicular phase of the menstrual cycle. To make the forearm ischemic prior to exercise, a 3 min period of circulatory arrest was achieved by inflating an upper arm cuff to supra systolic pressure. This cuff remained inflated for 2 min of isometric exercise at 30% of maximal voluntary contraction force, and 2 min of post‐exercise circulatory occlusion (PECO). Beat‐to‐beat heart rate (HR) (electrocardiography) and arterial BP (finger photopletysmography) were continuously measured. Beat‐to‐beat changes in stroke volume (SV) was obtained with Modelflow method and matched with the responses of heart rate (HR) to estimate Q̇ (Q̇=SV x HR) and TPR (TPR=Mean BP/Q). The exercise and PECO responses were analyzed using the peak change. Two trials were randomly conducted in different days either placebo or non‐selective β‐adrenergic blockade (40mg propranolol). During ischemic IHE under placebo condition, mean BP increased from rest in both men and women, however the magnitude of these responses was greater in men. During PECO, the mean BP remained elevated and the sex differences persisted. The β‐adrenergic blockade attenuated the mean BP response during ischemic IHE from rest in men (Δ 51 ± 6 mmHg vs Δ 39 ± 6 mmHg, P<0.01) but not in women (Δ 28 ± 5 mmHg vs Δ 32 ± 5mmHg, P=0.17). This attenuated mean BP response observed in men under β‐blockade could be explained by a reduction in Q̇ (Δ 3.0 ± 0.4l/min vs Δ 1.2 ± 0.2 l/min, P<0.01). This was less pronounced in women (Δ 2.0 ± 0.4 l/min vs Δ 1.0 ± 0.2 l/min, P=0.05). In addition, vascular constriction was increased during ischemic IHE and PECO in men and these responses were not affected by β‐blockade. In contrast, increases in TPR were greater in women under β‐adrenergic blockade during both ischemic IHE (Δ 1.2 ± 0.7 mmHg.L‐1.min vs Δ 3.3 ± 0.9 mmHg.L‐1.min, P=0.03) and PECO (Δ 4.5 ± 0.9 mmHg.L‐1.min vs Δ 6.8 ± 1.1 mmHg.L‐1.min, P=0.04). These findings demonstrate for the first time that the sex differences in arterial BP regulation during ischemic IHE are mediated by β‐adrenergic receptors. Support or Funding Information Funding: CNPq, FAPDF, CAPES and an American Physiological Society Arthur C. Guyton Awards for Excellence in Integrative Physiology (to L.C. Vianna). This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
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) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 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 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 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 ».