Myofilament lattice spacing as a function of sarcomere length in isolated rat myocardium

Thomas C. Irving, John Konhilas, Darold Perry, Robert Fischetti, Pieter P. De Tombe

Research output: Contribution to journalArticle

100 Citations (Scopus)

Abstract

The Frank-Starling relationship of the heart has, as its molecular basis, an increase in the activation of myofibrils by calcium as the sarcomere length increases. It has been suggested that this phenomenon may be due to myofilaments moving closer together at longer lengths, thereby enhancing the probability of favorable actomyosin interaction, resulting in increased calcium sensitivity. Accordingly, we have developed an apparatus so as to obtain accurate measurements of myocardial interfilament spacing (by synchrotron X-ray diffraction) as a function of sarcomere length (by video microscopy) over the working range of the heart, using skinned as well as intact rat trabeculas as model systems. In both these systems, lattice spacing decreased significantly as sarcomere length was increased. Furthermore, lattice spacing in the intact muscle was significantly smaller than that in the skinned muscle at all sarcomere lengths studied. These observations are consistent with the hypothesis that lattice spacing underlies length-dependent activation in the myocardium.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume279
Issue number5 48-5
StatePublished - 2000
Externally publishedYes

Fingerprint

Sarcomeres
Myofibrils
Myocardium
Calcium
Starlings
Video Microscopy
Actomyosin
Muscles
Synchrotrons
X-Ray Diffraction

Keywords

  • Length-dependent activation
  • Trabeculas
  • X-ray diffraction

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

Cite this

Myofilament lattice spacing as a function of sarcomere length in isolated rat myocardium. / Irving, Thomas C.; Konhilas, John; Perry, Darold; Fischetti, Robert; De Tombe, Pieter P.

In: American Journal of Physiology - Heart and Circulatory Physiology, Vol. 279, No. 5 48-5, 2000.

Research output: Contribution to journalArticle

Irving, Thomas C. ; Konhilas, John ; Perry, Darold ; Fischetti, Robert ; De Tombe, Pieter P. / Myofilament lattice spacing as a function of sarcomere length in isolated rat myocardium. In: American Journal of Physiology - Heart and Circulatory Physiology. 2000 ; Vol. 279, No. 5 48-5.
@article{2256c4b7719d43f694c121133e2bfe24,
title = "Myofilament lattice spacing as a function of sarcomere length in isolated rat myocardium",
abstract = "The Frank-Starling relationship of the heart has, as its molecular basis, an increase in the activation of myofibrils by calcium as the sarcomere length increases. It has been suggested that this phenomenon may be due to myofilaments moving closer together at longer lengths, thereby enhancing the probability of favorable actomyosin interaction, resulting in increased calcium sensitivity. Accordingly, we have developed an apparatus so as to obtain accurate measurements of myocardial interfilament spacing (by synchrotron X-ray diffraction) as a function of sarcomere length (by video microscopy) over the working range of the heart, using skinned as well as intact rat trabeculas as model systems. In both these systems, lattice spacing decreased significantly as sarcomere length was increased. Furthermore, lattice spacing in the intact muscle was significantly smaller than that in the skinned muscle at all sarcomere lengths studied. These observations are consistent with the hypothesis that lattice spacing underlies length-dependent activation in the myocardium.",
keywords = "Length-dependent activation, Trabeculas, X-ray diffraction",
author = "Irving, {Thomas C.} and John Konhilas and Darold Perry and Robert Fischetti and {De Tombe}, {Pieter P.}",
year = "2000",
language = "English (US)",
volume = "279",
journal = "American Journal of Physiology",
issn = "0363-6143",
publisher = "American Physiological Society",
number = "5 48-5",

}

TY - JOUR

T1 - Myofilament lattice spacing as a function of sarcomere length in isolated rat myocardium

AU - Irving, Thomas C.

AU - Konhilas, John

AU - Perry, Darold

AU - Fischetti, Robert

AU - De Tombe, Pieter P.

PY - 2000

Y1 - 2000

N2 - The Frank-Starling relationship of the heart has, as its molecular basis, an increase in the activation of myofibrils by calcium as the sarcomere length increases. It has been suggested that this phenomenon may be due to myofilaments moving closer together at longer lengths, thereby enhancing the probability of favorable actomyosin interaction, resulting in increased calcium sensitivity. Accordingly, we have developed an apparatus so as to obtain accurate measurements of myocardial interfilament spacing (by synchrotron X-ray diffraction) as a function of sarcomere length (by video microscopy) over the working range of the heart, using skinned as well as intact rat trabeculas as model systems. In both these systems, lattice spacing decreased significantly as sarcomere length was increased. Furthermore, lattice spacing in the intact muscle was significantly smaller than that in the skinned muscle at all sarcomere lengths studied. These observations are consistent with the hypothesis that lattice spacing underlies length-dependent activation in the myocardium.

AB - The Frank-Starling relationship of the heart has, as its molecular basis, an increase in the activation of myofibrils by calcium as the sarcomere length increases. It has been suggested that this phenomenon may be due to myofilaments moving closer together at longer lengths, thereby enhancing the probability of favorable actomyosin interaction, resulting in increased calcium sensitivity. Accordingly, we have developed an apparatus so as to obtain accurate measurements of myocardial interfilament spacing (by synchrotron X-ray diffraction) as a function of sarcomere length (by video microscopy) over the working range of the heart, using skinned as well as intact rat trabeculas as model systems. In both these systems, lattice spacing decreased significantly as sarcomere length was increased. Furthermore, lattice spacing in the intact muscle was significantly smaller than that in the skinned muscle at all sarcomere lengths studied. These observations are consistent with the hypothesis that lattice spacing underlies length-dependent activation in the myocardium.

KW - Length-dependent activation

KW - Trabeculas

KW - X-ray diffraction

UR - http://www.scopus.com/inward/record.url?scp=0033668412&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0033668412&partnerID=8YFLogxK

M3 - Article

VL - 279

JO - American Journal of Physiology

JF - American Journal of Physiology

SN - 0363-6143

IS - 5 48-5

ER -