The relationship between ciliary neurotrophic factor (CNTF) genotype and motor unit physiology: Preliminary studies

Robin A. Conwit, Shari Ling, Stephen Roth, Daniel Stashuk, Ben Hurley, Robert Ferrell, E. Metter

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Background: Ciliary neurotrophic factor (CNTF) is important for neuronal and muscle development, and genetic variation in the CNTF gene has been associated with muscle strength. The effect of CNTF on nerve development suggests that CNTF genotype may be associated with force production via its influence on motor unit size and firing patterns. The purpose of this study is to examine whether CNTF genotype differentially affects motor unit activation in the vastus medialis with increasing isometric force during knee extension. Results: Sixty-nine healthy subjects were genotyped for the presence of the G and A (null) alleles in the CNTF gene (n = 57 G/G, 12 G/A). They were tested using a dynamometer during submaximal isometric knee extension contractions that were from 10-50% of their maximal strength. During the contractions, the vastus medialis was studied using surface and intramuscular electromyography with spiked triggered averaging to assess surface-detected motor unit potential (SMUP) area and mean firing rates (mFR) from identified motor units. CNTF genotyping was performed using standard PCR techniques from DNA obtained from leucocytes of whole blood samples. The CNTF G/A genotype was associated with smaller SMUP area motor units and lower mFR at higher force levels, and fewer but larger units at lower force levels than G/G homozygotes. The two groups used motor units with different size and activation characteristics with increasing force generation. While G/G subjects tended to utilize larger motor units with increasing force, G/ A subjects showed relatively less increase in size by using relatively larger units at lower force levels. At higher force levels, G/A subjects were able to generate more force per motor unit size suggesting more efficient motor unit function with increasing muscle force. Conclusion: Differential motor unit responses were observed between CNTF genotypes at force levels utilized in daily activities.

Original languageEnglish (US)
Article number15
JournalBMC Physiology
Volume5
DOIs
StatePublished - Sep 23 2005
Externally publishedYes

Fingerprint

Ciliary Neurotrophic Factor
Genotype
Gravitation
Quadriceps Muscle
Knee
Muscle Development
Motor Cortex
Homozygote
Muscle Strength
Electromyography
Genes
Healthy Volunteers
Leukocytes
Alleles
Muscles
Polymerase Chain Reaction

All Science Journal Classification (ASJC) codes

  • Medicine(all)

Cite this

The relationship between ciliary neurotrophic factor (CNTF) genotype and motor unit physiology : Preliminary studies. / Conwit, Robin A.; Ling, Shari; Roth, Stephen; Stashuk, Daniel; Hurley, Ben; Ferrell, Robert; Metter, E.

In: BMC Physiology, Vol. 5, 15, 23.09.2005.

Research output: Contribution to journalArticle

Conwit, Robin A. ; Ling, Shari ; Roth, Stephen ; Stashuk, Daniel ; Hurley, Ben ; Ferrell, Robert ; Metter, E. / The relationship between ciliary neurotrophic factor (CNTF) genotype and motor unit physiology : Preliminary studies. In: BMC Physiology. 2005 ; Vol. 5.
@article{05762e7b74b445149e8f07b097275c9a,
title = "The relationship between ciliary neurotrophic factor (CNTF) genotype and motor unit physiology: Preliminary studies",
abstract = "Background: Ciliary neurotrophic factor (CNTF) is important for neuronal and muscle development, and genetic variation in the CNTF gene has been associated with muscle strength. The effect of CNTF on nerve development suggests that CNTF genotype may be associated with force production via its influence on motor unit size and firing patterns. The purpose of this study is to examine whether CNTF genotype differentially affects motor unit activation in the vastus medialis with increasing isometric force during knee extension. Results: Sixty-nine healthy subjects were genotyped for the presence of the G and A (null) alleles in the CNTF gene (n = 57 G/G, 12 G/A). They were tested using a dynamometer during submaximal isometric knee extension contractions that were from 10-50{\%} of their maximal strength. During the contractions, the vastus medialis was studied using surface and intramuscular electromyography with spiked triggered averaging to assess surface-detected motor unit potential (SMUP) area and mean firing rates (mFR) from identified motor units. CNTF genotyping was performed using standard PCR techniques from DNA obtained from leucocytes of whole blood samples. The CNTF G/A genotype was associated with smaller SMUP area motor units and lower mFR at higher force levels, and fewer but larger units at lower force levels than G/G homozygotes. The two groups used motor units with different size and activation characteristics with increasing force generation. While G/G subjects tended to utilize larger motor units with increasing force, G/ A subjects showed relatively less increase in size by using relatively larger units at lower force levels. At higher force levels, G/A subjects were able to generate more force per motor unit size suggesting more efficient motor unit function with increasing muscle force. Conclusion: Differential motor unit responses were observed between CNTF genotypes at force levels utilized in daily activities.",
author = "Conwit, {Robin A.} and Shari Ling and Stephen Roth and Daniel Stashuk and Ben Hurley and Robert Ferrell and E. Metter",
year = "2005",
month = "9",
day = "23",
doi = "10.1186/1472-6793-5-15",
language = "English (US)",
volume = "5",
journal = "BMC Physiology",
issn = "1472-6793",
publisher = "BioMed Central",

}

TY - JOUR

T1 - The relationship between ciliary neurotrophic factor (CNTF) genotype and motor unit physiology

T2 - Preliminary studies

AU - Conwit, Robin A.

AU - Ling, Shari

AU - Roth, Stephen

AU - Stashuk, Daniel

AU - Hurley, Ben

AU - Ferrell, Robert

AU - Metter, E.

PY - 2005/9/23

Y1 - 2005/9/23

N2 - Background: Ciliary neurotrophic factor (CNTF) is important for neuronal and muscle development, and genetic variation in the CNTF gene has been associated with muscle strength. The effect of CNTF on nerve development suggests that CNTF genotype may be associated with force production via its influence on motor unit size and firing patterns. The purpose of this study is to examine whether CNTF genotype differentially affects motor unit activation in the vastus medialis with increasing isometric force during knee extension. Results: Sixty-nine healthy subjects were genotyped for the presence of the G and A (null) alleles in the CNTF gene (n = 57 G/G, 12 G/A). They were tested using a dynamometer during submaximal isometric knee extension contractions that were from 10-50% of their maximal strength. During the contractions, the vastus medialis was studied using surface and intramuscular electromyography with spiked triggered averaging to assess surface-detected motor unit potential (SMUP) area and mean firing rates (mFR) from identified motor units. CNTF genotyping was performed using standard PCR techniques from DNA obtained from leucocytes of whole blood samples. The CNTF G/A genotype was associated with smaller SMUP area motor units and lower mFR at higher force levels, and fewer but larger units at lower force levels than G/G homozygotes. The two groups used motor units with different size and activation characteristics with increasing force generation. While G/G subjects tended to utilize larger motor units with increasing force, G/ A subjects showed relatively less increase in size by using relatively larger units at lower force levels. At higher force levels, G/A subjects were able to generate more force per motor unit size suggesting more efficient motor unit function with increasing muscle force. Conclusion: Differential motor unit responses were observed between CNTF genotypes at force levels utilized in daily activities.

AB - Background: Ciliary neurotrophic factor (CNTF) is important for neuronal and muscle development, and genetic variation in the CNTF gene has been associated with muscle strength. The effect of CNTF on nerve development suggests that CNTF genotype may be associated with force production via its influence on motor unit size and firing patterns. The purpose of this study is to examine whether CNTF genotype differentially affects motor unit activation in the vastus medialis with increasing isometric force during knee extension. Results: Sixty-nine healthy subjects were genotyped for the presence of the G and A (null) alleles in the CNTF gene (n = 57 G/G, 12 G/A). They were tested using a dynamometer during submaximal isometric knee extension contractions that were from 10-50% of their maximal strength. During the contractions, the vastus medialis was studied using surface and intramuscular electromyography with spiked triggered averaging to assess surface-detected motor unit potential (SMUP) area and mean firing rates (mFR) from identified motor units. CNTF genotyping was performed using standard PCR techniques from DNA obtained from leucocytes of whole blood samples. The CNTF G/A genotype was associated with smaller SMUP area motor units and lower mFR at higher force levels, and fewer but larger units at lower force levels than G/G homozygotes. The two groups used motor units with different size and activation characteristics with increasing force generation. While G/G subjects tended to utilize larger motor units with increasing force, G/ A subjects showed relatively less increase in size by using relatively larger units at lower force levels. At higher force levels, G/A subjects were able to generate more force per motor unit size suggesting more efficient motor unit function with increasing muscle force. Conclusion: Differential motor unit responses were observed between CNTF genotypes at force levels utilized in daily activities.

UR - http://www.scopus.com/inward/record.url?scp=26444607987&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=26444607987&partnerID=8YFLogxK

U2 - 10.1186/1472-6793-5-15

DO - 10.1186/1472-6793-5-15

M3 - Article

C2 - 16181490

AN - SCOPUS:26444607987

VL - 5

JO - BMC Physiology

JF - BMC Physiology

SN - 1472-6793

M1 - 15

ER -