| Differential effects of neonatal denervation on intrafusal muscle fibers in the rat. | |
| | |
MedLine Citation:
|
PMID: 8512092 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
The response of developing muscle spindles to denervation was studied by sectioning the nerve to the medial gastrocnemius muscle of rats at birth. The denervated spindles were examined daily throughout the first postnatal week for changes in ultrastructure and expression of several isoforms of myosin heavy chain (MHC). Each of the three different types of intrafusal muscle fiber exhibited a different response to denervation. Within 5 days after the nerve section nuclear bag2 fibers degenerated completely; nuclear bag1 fibers persisted, but ceased to express the 'spindle-specific' slow-tonic MHC isoform and thereby could not be differentiated from extrafusal fibers; nuclear chain fibers did not form. The capsules of spindles disassembled, hence spindles or their remnants could no longer be identified 1 week after denervation. Neonatal deefferentation has little effect on these features of developing spindles, so removal of afferent innervation is presumably the factor that induces the loss of spindles in denervated muscles. Degeneration of the bag2 fiber, but not bag1 or extrafusal fibers, reflects a greater dependence of the bag2 fiber than the bag1 fiber on afferent innervation for maintenance of its structural integrity. This difference in response of the two types of immature bag fiber to denervation might reflect an origin of the bag2 fibers from a lineage of myogenic cells distinct from that giving rise to bag1 or extrafusal fibers, or a difference in the length of contact with afferents between the two types of bag fiber prior to nerve section. |
| | |
Authors:
|
J Kucera; J M Walro; J Reichler |
Publication Detail:
|
Type: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
|
Title: Anatomy and embryology Volume: 187 ISSN: 0340-2061 ISO Abbreviation: Anat. Embryol. Publication Date: 1993 Apr |
Date Detail:
|
Created Date: 1993-07-15 Completed Date: 1993-07-15 Revised Date: 2007-11-14 |
Medline Journal Info:
|
Nlm Unique ID: 7505194 Medline TA: Anat Embryol (Berl) Country: GERMANY |
Other Details:
|
Languages: eng Pagination: 397-408 Citation Subset: IM |
Affiliation:
|
Department of Neurology, School of Medicine, Boston University, MA 02118. |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Animals Animals, Newborn Calmodulin-Binding Proteins* Microscopy, Electron Muscle Denervation / adverse effects* Muscle Development Muscle Spindles / chemistry, cytology, growth & development, pathology*, ultrastructure Muscles / chemistry, drug effects, pathology* Nerve Growth Factors / pharmacology Proteins / analysis* Rats Rats, Sprague-Dawley |
| Grant Support | |
ID/Acronym/Agency:
|
NS25796/NS/NINDS NIH HHS |
| Chemical | |
Reg. No./Substance:
|
0/Calmodulin-Binding Proteins; 0/Nerve Growth Factors; 0/Proteins |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Astroglial pattern in the spinal cord of the adult barbel (Barbus comiza).
Next Document: A prospective, comparative trial of three anesthetics for elective supratentorial craniotomy. Propof...