Muscle ultrastructure and biochemistry of lowland Tibetans.

Détails

ID Serval
serval:BIB_970A9E99DBE7
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Muscle ultrastructure and biochemistry of lowland Tibetans.
Périodique
Journal of Applied Physiology
Auteur(s)
Kayser B., Hoppeler H., Desplanches D., Marconi C., Broers B., Cerretelli P.
ISSN
8750-7587 (Print)
ISSN-L
0161-7567
Statut éditorial
Publié
Date de publication
1996
Volume
81
Numéro
1
Pages
419-425
Langue
anglais
Résumé
Muscle ultrastructure and biochemistry in vastus lateralis muscle biopsies and the response to exercise of 8 lowland Tibetans (T) were compared with those of 8 Nepalese lowlanders (N). Blood hemoglobin was lower in T than in N (119 +/- 3 vs. 131 +/- 2 g/l; P < 0.05). Peak O2 consumption per kilogram of body mass was similar [37.9 +/- 2.2 (T) vs. 40.1 +/- 1.36 ml.min-1.kg body mass-1 (N)]. Maximum exercise blood lactate was the same [11.4 (T) +/- 0.5 vs. 11.3 +/- 0.6 mM (N)]. Muscle fiber type distribution was similar [type I, 58.6 +/- 3.4 (N) vs. 57.0 +/- 3.4% (T); type IIa, 24.1 +/- 3.5 vs. 27.1 +/- 1.6%; type IIb, 17.4 +/- 1.4 vs. 15.9 +/- 2.9%]. T had smaller fiber cross-sectional areas [3,413 +/- 677 (T) vs. 3,895 +/- 447 microns 2 (N); P < 0.05] but had similar number of capillaries per muscle fiber [1.35 +/- 0.23 (T) vs. 1.46 +/- 0.08 (N)] and muscle fiber area supplied per capillary [399 +/- 29 (T) vs. 382 +/- 65 mm2 (N)]. Total mitochondrial volume density was much lower in T (3.99 +/- 0.17%) than in N (5.51 +/- 0.19%) (P < 0.025). Mirroring mitochondrial volume density, citrate synthase and 3-hydroxyacyl-CoA dehydrogenase activities were lower in T than in N (P < 0.05). The activities of L-lactate dehydrogenase and hexokinase were the same in both groups. T had significantly less muscle fiber lipid droplets than did N, which correlated with the low activity of 3-hydroxyacyl-CoA dehydrogenase (r = 0.57, P = 0.02). In conclusion, lowland-born T have a low mitochondrial volume-to-specific peak O2 consumption ratio, which, based on previous measurements on altitude-born Sherpas (B. Kayser, H. Hoppeler, H. Claassen and P. Cerretelli. J. Appl. Physiol. 70: 1938-1942, 1991), appears to be an inborn feature.
Mots-clé
Adolescent, Adult, Age Factors, Altitude, Anaerobic Threshold/physiology, Body Composition/physiology, Body Height/physiology, Body Weight, Exercise/physiology, Exercise Test, Female, Histocytochemistry, Humans, Male, Mitochondria, Muscle/metabolism, Mitochondria, Muscle/ultrastructure, Muscle Fibers, Skeletal/physiology, Muscle Fibers, Skeletal/ultrastructure, Muscle, Skeletal/metabolism, Muscle, Skeletal/ultrastructure, Nepal, Skinfold Thickness, Tibet
Pubmed
Web of science
Création de la notice
19/09/2013 11:04
Dernière modification de la notice
20/08/2019 15:59
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