umu.sePublications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Muscle spindles in the deep muscles of the human neck: a morphological and immunocytochemical study
Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy. Umeå University, Faculty of Medicine, Department of Clinical Sciences, Ophthalmology.
2003 (English)In: Journal of Histochemistry and Cytochemistry, ISSN 0022-1554, E-ISSN 1551-5044, Vol. 51, no 2, 175-186 p.Article in journal (Refereed) Published
Abstract [en]

Muscle spindle density is extremely high in the deep muscles of the human neck. However, there is a paucity of information regarding the morphology and immunoreactivity of these muscle spindles. The objective of this study was to investigate the intrafusal fiber content and to assess the myosin heavy chain (MyHC) composition of muscle spindles from human deep neck muscles. In addition to the conventional spindles containing bag(1), bag(2), and chain fibers (b(1)b(2)c spindle), we observed a number of spindles lacking bag(1) (b(2)c spindle) or bag(2) (b(1)c spindle) fibers. Both bag(1) and bag(2) fibers contained slow tonic MyHCs along their entire fiber length and MyHCI, MyHCIIa, embryonic, and alpha-cardiac MyHC isoforms along a variable length of the fibers. Fetal MyHC was present in bag(2) fibers but not in bag(1) fibers. Nuclear chain fibers contained MyHCIIa, embryonic, and fetal isoforms with regional variations. We also compared the present data with our previous results obtained from muscle spindles in human biceps brachii and the first lumbrical muscles. The allotment of numbers of intrafusal fibers and the MyHC composition showed some muscle-related differences, suggesting functional specialization in the control of movement among different human muscles.

Place, publisher, year, edition, pages
Sage Publications, 2003. Vol. 51, no 2, 175-186 p.
Keyword [en]
human, muscle spindle, deep neck muscles, mATPase, MyHC, intrafusal fibers
National Category
Medical and Health Sciences Ophthalmology Cell and Molecular Biology
Research subject
Human Anatomy; Ophtalmology
Identifiers
URN: urn:nbn:se:umu:diva-4213DOI: 10.1177/002215540305100206PubMedID: 12533526OAI: oai:DiVA.org:umu-4213DiVA: diva2:143215
Available from: 2004-11-09 Created: 2004-11-09 Last updated: 2013-12-12Bibliographically approved
In thesis
1. Human muscle spindles: complex morphology and structural organisation
Open this publication in new window or tab >>Human muscle spindles: complex morphology and structural organisation
2004 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Muscle spindles are skeletal muscle mechanoreceptors that mediate the stretch reflex and provide axial and limb position information to the central nervous system. They have been proposed to play a major role in the pathophysiology of muscle pain. Knowledge about the normal human muscle spindles is needed in order to understand their role in muscle disease or dysfunction.

The aim of this study was to investigate the fiber content and MyHC composition of the muscle spindles in the human biceps brachii (BB) and deep muscles of the neck (DN); to determine whether there are age-related changes in human muscle spindles with respect to structure and MyHC composition; to investigate the distribution of SERCA isoforms and to evaluate whether there is a coordinated expression of SERCA and MyHC isoforms in intrafusal fibers. The myosin heavy chain (MyHC) content correlates to contraction velocity and force and the sarcoplasmic reticulum Ca2+ ATPase (SERCA) is a major determinant of muscle fiber relaxation velocity.

Muscle specimens obtained from young and old subjects were serially sectioned and the pattern of distribution of different proteins along the length of the intrafusal fibers was revealed by immunocytochemistry. The MyHC content of single muscle spindles was assessed with SDS-PAGE and immunoblots.

There were clear differences between BB and DN with regard to the morphology and MyHC composition of muscle spindles. Virtually each muscle spindle in the BB, but not in the DN, had a unique allotment of numbers of bag1, bag2 and chain fibers. In DN, a number of muscle spindles lacked either bag1 or bag2 fibers. Four major MyHC isoforms (MyHCI, IIa, α-cardiac and intrafusal) were detected by SDS-PAGE. In both BB and DN, immunocytochemistry revealed co-expression of several MyHC isoforms in each intrafusal fiber and regional heterogeneity. Both nuclear bag1 and bag2 fibers contained slow tonic MyHC uniformly and MyHCI, α-cardiac, embryonic and fetal with regional variations. Nuclear chain fibers contained MyHCIIa, embryonic and fetal and in the BB also MyHCIIx.

The total number of intrafusal fibers per spindle decreased significantly with aging, due to a significant reduction in the number of nuclear chain fibers. The patterns of MyHC expression were also affected by aging.

The bag1 fibers predominantly contained both SERCA isoforms in the encapsulated region. The bag2 fibers were more heterogeneous in their SERCA composition and 16-27% of them lacked both isoforms. Chain fibers contained SERCA1. There was a poor correlation between the MyHC and SERCA isoforms in nuclear bag fibers, whereas a strong correlation existed between MyHCIIa and SERCA1 in the nuclear chain fibers.

Human muscle spindles, each being unique, proved to be more complex than anticipated. The clear differences shown between the BB and DN muscle spindles suggest functional specialization in the control of movement among different human muscles. Aging apparently had profound effects on intrafusal fiber content and MyHC composition. The age-related changes in muscle spindle phenotype may reflect deterioration in sensory and motor innervation and are likely to have a detrimental impact on motor control in the elderly.

Publisher
49 p.
Series
Umeå University medical dissertations, ISSN 0346-6612 ; 928
Keyword
human, muscle spindle, intrafusal fiber, aging, biceps brachii, deep muscles of the neck, MyHC, mATPase, SERCA
Research subject
Human Anatomy
Identifiers
urn:nbn:se:umu:diva-356 (URN)91-7305-762-2 (ISBN)
Public defence
2004-11-25, Stora föreläsningssalen, Biologihuset, Umeå universitet, Umeå, 09:00 (English)
Opponent
Available from: 2004-11-09 Created: 2004-11-09 Last updated: 2010-08-05Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textPubMed

Search in DiVA

By author/editor
Liu, Jing-XiaThornell, Lars-EricPedrosa-Domellöf, Fatima
By organisation
AnatomyOphthalmology
In the same journal
Journal of Histochemistry and Cytochemistry
Medical and Health SciencesOphthalmologyCell and Molecular Biology

Search outside of DiVA

GoogleGoogle Scholar

doi
pubmed
urn-nbn

Altmetric score

doi
pubmed
urn-nbn
Total: 159 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf