Related Experiment Video

Updated: Aug 9, 2026

Analysis of Cardiomyocyte Development using Immunofluorescence in Embryonic Mouse Heart
10:56

Analysis of Cardiomyocyte Development using Immunofluorescence in Embryonic Mouse Heart

Published on: March 26, 2015

Postnatal development of myosin heavy chain isoforms in rat extraocular muscles

Sang Jin Lim1, Hak Hyun Jung, Yoonae A Cho

  • 1Department of Ophthalmology, Korea University College of Medicine, Sungbuk-Ku, Seoul, Republic of Korea.

Molecular Vision
|April 11, 2006
PubMed

Insights

Rat extraocular muscles (EOMs) show a developmental shift in myosin heavy chain (MHC) isoforms, transitioning from neonatal MHC to fast MHC types after birth, with distinct adult EOM compositions.

Area of Science:

  • Muscle physiology
  • Developmental biology
  • Molecular biology

Background:

  • Extraocular muscles (EOMs) have unique functional demands.
  • Myosin heavy chain (MHC) isoforms determine muscle fiber type and contractile properties.
  • Understanding MHC isoform development in EOMs is crucial for comprehending muscle adaptation.

Purpose of the Study:

  • To investigate the myosin heavy chain (MHC) isoform composition in rat extraocular muscles (EOMs) during postnatal development.
  • To analyze changes in MHC expression from birth to adulthood.

Main Methods:

  • Competitive polymerase chain reaction (PCR) was used to quantify MHC mRNA levels.
  • MHC composition was analyzed at postnatal day 0 (P0), postnatal day 14 (P14), and in adult rats.
  • Specific analysis of MHC isoforms in each of the six adult EOMs was performed.

Main Results:

  • At P0, neonatal MHC predominated (75.5%), with smaller amounts of embryonic MHC and 2A MHC.
  • By P14, 2X MHC (42.4%) and 2A MHC (27.4%) became dominant, while neonatal and embryonic MHC decreased.
  • Adult EOMs primarily expressed fast MHC isoforms (2X, 2A, 2B), with variations among the six EOMs.

Conclusions:

  • A strong correlation exists between fast MHC isoform composition and muscle development.
  • MHC isoform expression follows a neonatal-2X-2B pattern post-birth in EOMs.
  • Postnatal EOM development exhibits unique MHC expression patterns potentially linked to functional requirements.
Abstract

More Related Videos

Isolation and Characterization of Satellite Cells from Rat Head Branchiomeric Muscles07:37

Isolation and Characterization of Satellite Cells from Rat Head Branchiomeric Muscles

Published on: July 20, 2015

Analysis of Cardiac Contractile Dysfunction and Ca2+ Transients in Rodent Myocytes07:32

Analysis of Cardiac Contractile Dysfunction and Ca2+ Transients in Rodent Myocytes

Published on: May 25, 2022

Related Concept Videos

Overview of Myosin Structure and Function01:15

Overview of Myosin Structure and Function

Myosins are a family of molecular motor proteins, first identified in the skeletal muscles, where they are responsible for muscle contraction. Along with their role in muscle contraction, these proteins also play a role in the intracellular transport of molecules and vesicles. There are twenty-four classes of myosins based on their domain sequence and organization. Of the twenty-four, six classes (Myosin I, Myosin II, Myosin V, Myosin VI, Myosin VII, and Myosin X)  have been well characterized.
Muscles of the Eye01:20

Muscles of the Eye

The muscles of the eye are sophisticated structures that control eye movement and focus, allowing for the precise and rapid adjustments necessary for vision. The human eye is controlled by ten muscles — six extraocular muscles, three intraocular muscles, and one primary eyelid retractor muscle.
Extraocular Muscles
The six extraocular muscles surround the eyeball and control its movements. They are responsible for a wide range of eye motions, including looking up, down, left, right, and rotating...