The role of chronic muscle (in)activity on carnosine homeostasis: a study with spinal-cord injured athletes

Nemezio, K., de Carvalho Yamaguchi, G., Ramkrapes, A.P.B., Schulz, M.L., Baptista, I.L., Riani, L.A., de Souza Gonçalves, L., Sale, C. ORCID: 0000-0002-5816-4169, de Medeiros, M.H.G., Gualano, B. and Artioli, G.G. ORCID: 0000-0001-8463-2213, 2021. The role of chronic muscle (in)activity on carnosine homeostasis: a study with spinal-cord injured athletes. American Journal of Physiology-Regulatory, Integrative and Comparative Physiology. ISSN 0363-6119

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Abstract

To examine the role of chronic (in)activity on muscle carnosine (MCarn) and how chronic (in)activity affects MCarn responses to β-alanine supplementation in spinal-cord injured athletes, sixteen male athletes with paraplegia were randomized (2:1 ratio) to receive β-alanine (n=11) or placebo (PL, n=5). They consumed 6.4 g‧d-1 of β-alanine or PL for 28 days. Muscle biopsies of the active deltoid and the inactive vastus lateralis (VL) were taken before and after supplementation. MCarn in the VL was also compared with the VL of a group of individuals without paraplegia (n=15). MCarn was quantified in whole muscle and in pools of individual fibers by High-performance Liquid Chromatography. MCarn was higher in chronically inactive VL vs. well-trained deltoid (32.0±12.0 vs. 20.5±6.1 mmol‧kg-1 DM; p=0.018). MCarn was higher in inactive vs. active VL (32.0±12.0 vs. 21.2±7.5 mmol‧kg-1 DM; p=0.011). In type-I fibers, MCarn was significantly higher in the inactive VL than in the active deltoid (38.3±4.7 vs. 27.3±11.8 mmol‧kg-1 DM, p=0.014). MCarn increased similarly between inactive VL and active deltoid in the β-alanine group (VL: 68.9±55.1%, p=0.0002; deltoid: 90.5±51.4%, p<0.0001), with no changes in the PL group. MCarn content was higher in the inactive VL than in the active deltoid and the active VL, but this is probably a consequence of fiber type shift (type I to type II) that occurs with chronic inactivity. Chronically inactive muscle showed an increase in MCarn after BA supplementation equally to the active muscle, suggesting that carnosine accretion following β-alanine supplementation is not influenced by muscle inactivity.

Item Type: Journal article
Alternative Title: Chronic muscle inactivity and muscle carnosine content [running title]
Publication Title: American Journal of Physiology-Regulatory, Integrative and Comparative Physiology
Creators: Nemezio, K., de Carvalho Yamaguchi, G., Ramkrapes, A.P.B., Schulz, M.L., Baptista, I.L., Riani, L.A., de Souza Gonçalves, L., Sale, C., de Medeiros, M.H.G., Gualano, B. and Artioli, G.G.
Publisher: American Physiological Society
Date: 31 March 2021
ISSN: 0363-6119
Identifiers:
NumberType
10.1152/ajpregu.00360.2020DOI
1430855Other
Divisions: Schools > School of Science and Technology
Record created by: Linda Sullivan
Date Added: 14 Apr 2021 11:06
Last Modified: 31 May 2021 15:04
URI: http://irep.ntu.ac.uk/id/eprint/42700

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