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Myosin isoforms and muscle fiber characteristics in equine gluteus medius muscle.
Anat Rec. 1996 Apr; 244(4):444-51.AR

Abstract

BACKGROUND

To date, four different myosin heavy chain (MyHC) isoforms have been identified in adult skeletal muscle of a number of species: types I, IIa, IIx or IId, and IIb. The aim of this study was to investigate the distribution of various MyHC isoforms in the equine gluteus medius and gluteus profundus muscles in relation with several morphometric variables of muscle fibers.

METHODS

Samples from different depths of the gluteus medius muscle (2, 4, 6, and 8 cm) and gluteus profundus muscle of five sedentary horses were examined by MyHC gel electrophoresis, monoclonal antibodies staining against fast, slow and neonatal MyHC isoforms, myosin adenosine triphosphatase (m-ATPase) activity, nicotinamide adenine dinucleotide tetrazolium reductase, alpha-glycerophosphate dehydrogenase, and alpha-amylase-PAS. Data about relative frequencies, sizes, and capillaries of the various histochemical fiber types were collected by morphometry.

RESULTS

Three MyHC isoforms were present in the gluteus medius muscle. Two of them comigrated with type I and IIa MyHC isoforms of rat diaphragm (used as a control). The third isoform showed an electrophoretic mobility closer to type IIx than to the IIb MyHC isoform of rat diaphragm. Only two MyHC isoforms (type I and IIa) were detected in the gluteus profundus muscle. In both muscles, type I fibers (high m-ATPase activity at pH 4.5) only reacted with the anti slow-MyHC antibody and both type IIA and IIB fibers (low and moderate m-ATPase activity at pH 4.5, respectively) only reacted with the anti fast-MyHC antibody. No cross-reactivity of fibers positive for both antibodies was found except for the scarce type IIC fibers. Fiber types and capillaries were heterogeneously distributed across the gluteus medius muscle. The deeper regions of this muscle were found to contain a higher percentage of type I fibers, a large number of capillaries and a lower proportion of type IIB fibers compared to the superficial regions of the muscle. The gluteus profundus muscle had more abundant and larger type I fibers than the deepest sampling site of the gluteus medius muscle.

CONCLUSIONS

These results show the existence of three different MyHC isoforms in the equine gluteus medius muscle and that fiber types and MyHC isoforms are heterogeneously distributed within this muscle. The distribution of slow-twitch and fast-twitch MyHCs among the fibers determined by immunohistochemistry was in agreement with histochemically identified type I and type II fibers, respectively.

Authors+Show Affiliations

Department of Comparative Anatomy and Pathological Anatomy, Faculty of Veterinary Sciences, University of Córdoba, Spain.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

8694280

Citation

Serrano, A L., et al. "Myosin Isoforms and Muscle Fiber Characteristics in Equine Gluteus Medius Muscle." The Anatomical Record, vol. 244, no. 4, 1996, pp. 444-51.
Serrano AL, Petrie JL, Rivero JL, et al. Myosin isoforms and muscle fiber characteristics in equine gluteus medius muscle. Anat Rec. 1996;244(4):444-51.
Serrano, A. L., Petrie, J. L., Rivero, J. L., & Hermanson, J. W. (1996). Myosin isoforms and muscle fiber characteristics in equine gluteus medius muscle. The Anatomical Record, 244(4), 444-51.
Serrano AL, et al. Myosin Isoforms and Muscle Fiber Characteristics in Equine Gluteus Medius Muscle. Anat Rec. 1996;244(4):444-51. PubMed PMID: 8694280.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Myosin isoforms and muscle fiber characteristics in equine gluteus medius muscle. AU - Serrano,A L, AU - Petrie,J L, AU - Rivero,J L, AU - Hermanson,J W, PY - 1996/4/1/pubmed PY - 2000/6/20/medline PY - 1996/4/1/entrez SP - 444 EP - 51 JF - The Anatomical record JO - Anat Rec VL - 244 IS - 4 N2 - BACKGROUND: To date, four different myosin heavy chain (MyHC) isoforms have been identified in adult skeletal muscle of a number of species: types I, IIa, IIx or IId, and IIb. The aim of this study was to investigate the distribution of various MyHC isoforms in the equine gluteus medius and gluteus profundus muscles in relation with several morphometric variables of muscle fibers. METHODS: Samples from different depths of the gluteus medius muscle (2, 4, 6, and 8 cm) and gluteus profundus muscle of five sedentary horses were examined by MyHC gel electrophoresis, monoclonal antibodies staining against fast, slow and neonatal MyHC isoforms, myosin adenosine triphosphatase (m-ATPase) activity, nicotinamide adenine dinucleotide tetrazolium reductase, alpha-glycerophosphate dehydrogenase, and alpha-amylase-PAS. Data about relative frequencies, sizes, and capillaries of the various histochemical fiber types were collected by morphometry. RESULTS: Three MyHC isoforms were present in the gluteus medius muscle. Two of them comigrated with type I and IIa MyHC isoforms of rat diaphragm (used as a control). The third isoform showed an electrophoretic mobility closer to type IIx than to the IIb MyHC isoform of rat diaphragm. Only two MyHC isoforms (type I and IIa) were detected in the gluteus profundus muscle. In both muscles, type I fibers (high m-ATPase activity at pH 4.5) only reacted with the anti slow-MyHC antibody and both type IIA and IIB fibers (low and moderate m-ATPase activity at pH 4.5, respectively) only reacted with the anti fast-MyHC antibody. No cross-reactivity of fibers positive for both antibodies was found except for the scarce type IIC fibers. Fiber types and capillaries were heterogeneously distributed across the gluteus medius muscle. The deeper regions of this muscle were found to contain a higher percentage of type I fibers, a large number of capillaries and a lower proportion of type IIB fibers compared to the superficial regions of the muscle. The gluteus profundus muscle had more abundant and larger type I fibers than the deepest sampling site of the gluteus medius muscle. CONCLUSIONS: These results show the existence of three different MyHC isoforms in the equine gluteus medius muscle and that fiber types and MyHC isoforms are heterogeneously distributed within this muscle. The distribution of slow-twitch and fast-twitch MyHCs among the fibers determined by immunohistochemistry was in agreement with histochemically identified type I and type II fibers, respectively. SN - 0003-276X UR - https://www.unboundmedicine.com/medline/citation/8694280/Myosin_isoforms_and_muscle_fiber_characteristics_in_equine_gluteus_medius_muscle_ L2 - https://doi.org/10.1002/(SICI)1097-0185(199604)244:4<444::AID-AR3>3.0.CO;2-V DB - PRIME DP - Unbound Medicine ER -