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Updated: Jul 13, 2026

Physiological Recordings of High and Low Output NMJs on the Crayfish Leg Extensor Muscle
Published on: November 17, 2010
Muscle type-specific myosin isoforms in crustacean muscles.
W A LaFramboise1, B Griffis, P Bonner
1Department of Pediatrics, Laboratory of Cellular and Molecular Myology, Allegheny University of the Health Sciences, Pittsburgh, Pennsylvania 15024, USA.
Skeletal muscle diversity arises from differential expression of myosin heavy chain (MyHC) genes. Crayfish muscle analysis reveals MyHC profiles correlate with specific innervation and function, supporting extrinsic control of muscle properties.
Area of Science:
- Muscle physiology
- Molecular biology
- Comparative zoology
Background:
- Skeletal muscle exhibits diverse physiological, histochemical, and enzymatic properties.
- Myosin heavy chain (MyHC) gene expression is a key determinant of muscle characteristics.
- Hypotheses for myofiber diversity include intrinsic (lineage) and extrinsic (innervation, hormones, usage) factors.
Purpose of the Study:
- To investigate the relationship between muscle innervation, function, and MyHC gene expression in crayfish (Procambarus clarkii).
- To test hypotheses regarding extrinsic control of myofiber diversity using a model system with specialized musculature.
Main Methods:
- Analysis of appendicular and abdominal musculature in crayfish.
- High-resolution SDS-PAGE to determine MyHC profiles.
- Correlation of MyHC expression patterns with motoneuron innervation type (tonic vs. phasic).
Main Results:
- Leg opener and superficial abdominal extensor muscles (tonic innervation) share an identical MyHC profile.
- Deep abdominal extensor muscles (phasic innervation) exhibit distinct MyHC profiles.
- Claw closer muscles (dual innervation) display a mixed MyHC phenotype, biased toward the phasic profile.
Conclusions:
- Multiple MyHC isoforms are present and differentially expressed in crayfish.
- Differential MyHC expression is associated with specific muscle types and functions.
- Results support the role of extrinsic factors, particularly innervation, in regulating muscle diversity.
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