Alteration of contractile force and mass in the senescent diaphragm with β2-agonist treatment

Wesley Smith, Amie Dirks, Takao Sugiura, Susan Muller, Phillip Scarpace, Scott K. Powers

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

Aging is associated with a decrease in diaphragmatic maximal tetanic force production (Po) in senescent rats. Treatment with the β2-agonist clenbuterol (CB) has been shown to increase skeletal muscle mass and Po in weak locomotor skeletal muscles from dystrophic rodents. It is unknown whether CB can increase diaphragmatic mass and Po in senescent rats. Therefore, we tested the hypothesis that CB treatment will increase specific Po (i.e., force per cross-sectional area) and mass in the diaphragm of old rats. Young (5 mo) and old (23 mo) male Fischer 344 rats were randomly assigned to one of the following groups (n = 10/group): 1) young CB treated; 2) young control; 3) old CB treated; and 4) old control. Animals were injected daily with either CB (2 mg/kg) or saline for 28 days. CB increased (P <0.05) the mass of the costal diaphragm in both young and old animals. CB treatment increased diaphragmatic-specific Po in old animals (∼15%; P <0.05) but did not alter (P > 0.05) diaphragmatic-specific Po in young animals. Biochemical analysis indicated that the improved maximal specific Po in the diaphragm of CB-treated old animals was not due to increased myofibrillar protein concentration. Analysis of the myosin heavy chain (MHC) content of the costal diaphragm revealed a CB-induced increase (P <0.05) in type IIb MHC and a decrease in type I, IIa, and IIx MHC in both young and old animals. These data support the hypothesis that CB treatment can restore the age-associated decline in both diaphragmatic-specific Po and muscle mass.

Original languageEnglish (US)
Pages (from-to)941-948
Number of pages8
JournalJournal of Applied Physiology
Volume92
Issue number3
StatePublished - 2002
Externally publishedYes

Fingerprint

Clenbuterol
Diaphragm
Myosin Heavy Chains
Skeletal Muscle
Inbred F344 Rats
Rodentia

Keywords

  • Clenbuterol
  • Myosin heavy chain
  • Sarcopenia

ASJC Scopus subject areas

  • Physiology
  • Endocrinology
  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation

Cite this

Smith, W., Dirks, A., Sugiura, T., Muller, S., Scarpace, P., & Powers, S. K. (2002). Alteration of contractile force and mass in the senescent diaphragm with β2-agonist treatment. Journal of Applied Physiology, 92(3), 941-948.

Alteration of contractile force and mass in the senescent diaphragm with β2-agonist treatment. / Smith, Wesley; Dirks, Amie; Sugiura, Takao; Muller, Susan; Scarpace, Phillip; Powers, Scott K.

In: Journal of Applied Physiology, Vol. 92, No. 3, 2002, p. 941-948.

Research output: Contribution to journalArticle

Smith, W, Dirks, A, Sugiura, T, Muller, S, Scarpace, P & Powers, SK 2002, 'Alteration of contractile force and mass in the senescent diaphragm with β2-agonist treatment', Journal of Applied Physiology, vol. 92, no. 3, pp. 941-948.
Smith W, Dirks A, Sugiura T, Muller S, Scarpace P, Powers SK. Alteration of contractile force and mass in the senescent diaphragm with β2-agonist treatment. Journal of Applied Physiology. 2002;92(3):941-948.
Smith, Wesley ; Dirks, Amie ; Sugiura, Takao ; Muller, Susan ; Scarpace, Phillip ; Powers, Scott K. / Alteration of contractile force and mass in the senescent diaphragm with β2-agonist treatment. In: Journal of Applied Physiology. 2002 ; Vol. 92, No. 3. pp. 941-948.
@article{2a52481941d0410594d6f336fff0d1f3,
title = "Alteration of contractile force and mass in the senescent diaphragm with β2-agonist treatment",
abstract = "Aging is associated with a decrease in diaphragmatic maximal tetanic force production (Po) in senescent rats. Treatment with the β2-agonist clenbuterol (CB) has been shown to increase skeletal muscle mass and Po in weak locomotor skeletal muscles from dystrophic rodents. It is unknown whether CB can increase diaphragmatic mass and Po in senescent rats. Therefore, we tested the hypothesis that CB treatment will increase specific Po (i.e., force per cross-sectional area) and mass in the diaphragm of old rats. Young (5 mo) and old (23 mo) male Fischer 344 rats were randomly assigned to one of the following groups (n = 10/group): 1) young CB treated; 2) young control; 3) old CB treated; and 4) old control. Animals were injected daily with either CB (2 mg/kg) or saline for 28 days. CB increased (P <0.05) the mass of the costal diaphragm in both young and old animals. CB treatment increased diaphragmatic-specific Po in old animals (∼15{\%}; P <0.05) but did not alter (P > 0.05) diaphragmatic-specific Po in young animals. Biochemical analysis indicated that the improved maximal specific Po in the diaphragm of CB-treated old animals was not due to increased myofibrillar protein concentration. Analysis of the myosin heavy chain (MHC) content of the costal diaphragm revealed a CB-induced increase (P <0.05) in type IIb MHC and a decrease in type I, IIa, and IIx MHC in both young and old animals. These data support the hypothesis that CB treatment can restore the age-associated decline in both diaphragmatic-specific Po and muscle mass.",
keywords = "Clenbuterol, Myosin heavy chain, Sarcopenia",
author = "Wesley Smith and Amie Dirks and Takao Sugiura and Susan Muller and Phillip Scarpace and Powers, {Scott K.}",
year = "2002",
language = "English (US)",
volume = "92",
pages = "941--948",
journal = "Journal of Applied Physiology",
issn = "8750-7587",
publisher = "American Physiological Society",
number = "3",

}

TY - JOUR

T1 - Alteration of contractile force and mass in the senescent diaphragm with β2-agonist treatment

AU - Smith, Wesley

AU - Dirks, Amie

AU - Sugiura, Takao

AU - Muller, Susan

AU - Scarpace, Phillip

AU - Powers, Scott K.

PY - 2002

Y1 - 2002

N2 - Aging is associated with a decrease in diaphragmatic maximal tetanic force production (Po) in senescent rats. Treatment with the β2-agonist clenbuterol (CB) has been shown to increase skeletal muscle mass and Po in weak locomotor skeletal muscles from dystrophic rodents. It is unknown whether CB can increase diaphragmatic mass and Po in senescent rats. Therefore, we tested the hypothesis that CB treatment will increase specific Po (i.e., force per cross-sectional area) and mass in the diaphragm of old rats. Young (5 mo) and old (23 mo) male Fischer 344 rats were randomly assigned to one of the following groups (n = 10/group): 1) young CB treated; 2) young control; 3) old CB treated; and 4) old control. Animals were injected daily with either CB (2 mg/kg) or saline for 28 days. CB increased (P <0.05) the mass of the costal diaphragm in both young and old animals. CB treatment increased diaphragmatic-specific Po in old animals (∼15%; P <0.05) but did not alter (P > 0.05) diaphragmatic-specific Po in young animals. Biochemical analysis indicated that the improved maximal specific Po in the diaphragm of CB-treated old animals was not due to increased myofibrillar protein concentration. Analysis of the myosin heavy chain (MHC) content of the costal diaphragm revealed a CB-induced increase (P <0.05) in type IIb MHC and a decrease in type I, IIa, and IIx MHC in both young and old animals. These data support the hypothesis that CB treatment can restore the age-associated decline in both diaphragmatic-specific Po and muscle mass.

AB - Aging is associated with a decrease in diaphragmatic maximal tetanic force production (Po) in senescent rats. Treatment with the β2-agonist clenbuterol (CB) has been shown to increase skeletal muscle mass and Po in weak locomotor skeletal muscles from dystrophic rodents. It is unknown whether CB can increase diaphragmatic mass and Po in senescent rats. Therefore, we tested the hypothesis that CB treatment will increase specific Po (i.e., force per cross-sectional area) and mass in the diaphragm of old rats. Young (5 mo) and old (23 mo) male Fischer 344 rats were randomly assigned to one of the following groups (n = 10/group): 1) young CB treated; 2) young control; 3) old CB treated; and 4) old control. Animals were injected daily with either CB (2 mg/kg) or saline for 28 days. CB increased (P <0.05) the mass of the costal diaphragm in both young and old animals. CB treatment increased diaphragmatic-specific Po in old animals (∼15%; P <0.05) but did not alter (P > 0.05) diaphragmatic-specific Po in young animals. Biochemical analysis indicated that the improved maximal specific Po in the diaphragm of CB-treated old animals was not due to increased myofibrillar protein concentration. Analysis of the myosin heavy chain (MHC) content of the costal diaphragm revealed a CB-induced increase (P <0.05) in type IIb MHC and a decrease in type I, IIa, and IIx MHC in both young and old animals. These data support the hypothesis that CB treatment can restore the age-associated decline in both diaphragmatic-specific Po and muscle mass.

KW - Clenbuterol

KW - Myosin heavy chain

KW - Sarcopenia

UR - http://www.scopus.com/inward/record.url?scp=0036095486&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0036095486&partnerID=8YFLogxK

M3 - Article

C2 - 11842024

AN - SCOPUS:0036095486

VL - 92

SP - 941

EP - 948

JO - Journal of Applied Physiology

JF - Journal of Applied Physiology

SN - 8750-7587

IS - 3

ER -