The force dependence of isometric and concentric potentiation in mouse muscle with and without skeletal myosin light chain kinase

William Gittings, Harish Aggarwal, James T. Stull, Rene Vandenboom

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

The isometric potentiation associated with myosin phosphorylation is force dependent. The purpose of this study was to assess the influence of a pre-existing period of isometric force on the concentric force potentiation displayed by mouse muscles with and without the ability to phosphorylate myosin. We tested isometric (ISO) and concentric (CON) potentiation, as well as concentric potentiation after isometric force (ISO-CON), in muscles from wild-type (WT) and skeletal myosin light chain kinase-deficient (skMLCK-/-) mice. A conditioning stimulus increased (i.e., potentiated) mean concentric force in the ISO-CON and CON conditions to 1.31 � ± 0.02 and 1.35 � ± 0.02 (WT) and to 1.19 � ± 0.02 and 1.21 �} 0.01 (skMLCK-/-) of prestimulus levels, respectively (data n = 6–8, p < 0.05). No potentiation of mean isometric force was observed in either genotype. The potentiation of mean concentric force was inversely related to relative tetanic force level (P/Po) in both genotypes. Moreover, concentric potentiation varied greatly within each contraction type and was negatively correlated with unpotentiated force in both genotypes. Thus, although no effect of pre-existing force was observed, strong and inverse relationships between concentric force potentiation and unpotentiated concentric force may suggest an influence of attached and force-generating crossbridges on potentiation magnitude in both WT and skMLCK-/- muscles.

Original languageEnglish (US)
Pages (from-to)23-32
Number of pages10
JournalCanadian Journal of Physiology and Pharmacology
Volume93
Issue number1
StatePublished - Oct 14 2014

Fingerprint

Myosin-Light-Chain Kinase
Genotype
Myosins
Muscles
Skeletal Muscle
Phosphorylation

Keywords

  • Concentric
  • Cooperativity
  • Isometric
  • Myosin
  • Phosphorylation
  • Regulatory light chains
  • Shortening ramps
  • skMLCK knockout
  • Tetanus

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)
  • Pharmacology

Cite this

The force dependence of isometric and concentric potentiation in mouse muscle with and without skeletal myosin light chain kinase. / Gittings, William; Aggarwal, Harish; Stull, James T.; Vandenboom, Rene.

In: Canadian Journal of Physiology and Pharmacology, Vol. 93, No. 1, 14.10.2014, p. 23-32.

Research output: Contribution to journalArticle

@article{12d7ce1011b4468f8330fba1ebef6c59,
title = "The force dependence of isometric and concentric potentiation in mouse muscle with and without skeletal myosin light chain kinase",
abstract = "The isometric potentiation associated with myosin phosphorylation is force dependent. The purpose of this study was to assess the influence of a pre-existing period of isometric force on the concentric force potentiation displayed by mouse muscles with and without the ability to phosphorylate myosin. We tested isometric (ISO) and concentric (CON) potentiation, as well as concentric potentiation after isometric force (ISO-CON), in muscles from wild-type (WT) and skeletal myosin light chain kinase-deficient (skMLCK-/-) mice. A conditioning stimulus increased (i.e., potentiated) mean concentric force in the ISO-CON and CON conditions to 1.31 � ± 0.02 and 1.35 � ± 0.02 (WT) and to 1.19 � ± 0.02 and 1.21 �} 0.01 (skMLCK-/-) of prestimulus levels, respectively (data n = 6–8, p < 0.05). No potentiation of mean isometric force was observed in either genotype. The potentiation of mean concentric force was inversely related to relative tetanic force level (P/Po) in both genotypes. Moreover, concentric potentiation varied greatly within each contraction type and was negatively correlated with unpotentiated force in both genotypes. Thus, although no effect of pre-existing force was observed, strong and inverse relationships between concentric force potentiation and unpotentiated concentric force may suggest an influence of attached and force-generating crossbridges on potentiation magnitude in both WT and skMLCK-/- muscles.",
keywords = "Concentric, Cooperativity, Isometric, Myosin, Phosphorylation, Regulatory light chains, Shortening ramps, skMLCK knockout, Tetanus",
author = "William Gittings and Harish Aggarwal and Stull, {James T.} and Rene Vandenboom",
year = "2014",
month = "10",
day = "14",
language = "English (US)",
volume = "93",
pages = "23--32",
journal = "Canadian Journal of Physiology and Pharmacology",
issn = "0008-4212",
publisher = "National Research Council of Canada",
number = "1",

}

TY - JOUR

T1 - The force dependence of isometric and concentric potentiation in mouse muscle with and without skeletal myosin light chain kinase

AU - Gittings, William

AU - Aggarwal, Harish

AU - Stull, James T.

AU - Vandenboom, Rene

PY - 2014/10/14

Y1 - 2014/10/14

N2 - The isometric potentiation associated with myosin phosphorylation is force dependent. The purpose of this study was to assess the influence of a pre-existing period of isometric force on the concentric force potentiation displayed by mouse muscles with and without the ability to phosphorylate myosin. We tested isometric (ISO) and concentric (CON) potentiation, as well as concentric potentiation after isometric force (ISO-CON), in muscles from wild-type (WT) and skeletal myosin light chain kinase-deficient (skMLCK-/-) mice. A conditioning stimulus increased (i.e., potentiated) mean concentric force in the ISO-CON and CON conditions to 1.31 � ± 0.02 and 1.35 � ± 0.02 (WT) and to 1.19 � ± 0.02 and 1.21 �} 0.01 (skMLCK-/-) of prestimulus levels, respectively (data n = 6–8, p < 0.05). No potentiation of mean isometric force was observed in either genotype. The potentiation of mean concentric force was inversely related to relative tetanic force level (P/Po) in both genotypes. Moreover, concentric potentiation varied greatly within each contraction type and was negatively correlated with unpotentiated force in both genotypes. Thus, although no effect of pre-existing force was observed, strong and inverse relationships between concentric force potentiation and unpotentiated concentric force may suggest an influence of attached and force-generating crossbridges on potentiation magnitude in both WT and skMLCK-/- muscles.

AB - The isometric potentiation associated with myosin phosphorylation is force dependent. The purpose of this study was to assess the influence of a pre-existing period of isometric force on the concentric force potentiation displayed by mouse muscles with and without the ability to phosphorylate myosin. We tested isometric (ISO) and concentric (CON) potentiation, as well as concentric potentiation after isometric force (ISO-CON), in muscles from wild-type (WT) and skeletal myosin light chain kinase-deficient (skMLCK-/-) mice. A conditioning stimulus increased (i.e., potentiated) mean concentric force in the ISO-CON and CON conditions to 1.31 � ± 0.02 and 1.35 � ± 0.02 (WT) and to 1.19 � ± 0.02 and 1.21 �} 0.01 (skMLCK-/-) of prestimulus levels, respectively (data n = 6–8, p < 0.05). No potentiation of mean isometric force was observed in either genotype. The potentiation of mean concentric force was inversely related to relative tetanic force level (P/Po) in both genotypes. Moreover, concentric potentiation varied greatly within each contraction type and was negatively correlated with unpotentiated force in both genotypes. Thus, although no effect of pre-existing force was observed, strong and inverse relationships between concentric force potentiation and unpotentiated concentric force may suggest an influence of attached and force-generating crossbridges on potentiation magnitude in both WT and skMLCK-/- muscles.

KW - Concentric

KW - Cooperativity

KW - Isometric

KW - Myosin

KW - Phosphorylation

KW - Regulatory light chains

KW - Shortening ramps

KW - skMLCK knockout

KW - Tetanus

UR - http://www.scopus.com/inward/record.url?scp=84920684228&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84920684228&partnerID=8YFLogxK

M3 - Article

VL - 93

SP - 23

EP - 32

JO - Canadian Journal of Physiology and Pharmacology

JF - Canadian Journal of Physiology and Pharmacology

SN - 0008-4212

IS - 1

ER -