Expression of myosin heavy chain (MyHC) isoforms in rat intrafusal muscle fibres after neonatal deefferentation and subsequent denervation.
The analysis of developing intrafusal fibres is not feasible in the absence of primary sensory axons, as neonatal denervation leads to the disintegration of muscle spindles. On the other hand, neonatal deefferentation does not arrest their differentiation and, moreover, it leads to the neomyogenesis of supernumerary intrafusal profiles. If the sciatic nerve was sectioned in 4-week-old rats deefferented at the birth, muscle spindles survived, the neomyogenesis proceeded and the denervated intrafusal fibres expressed the spindle specific slow tonic (STO) MyHC. The expression of MyHC pattern in individual fibres and the differentiation of the fibre type characteristics were, however, less obvious compared to the control or deefferented spindles. The newly formed intrafusal profiles (which differentiated from satellite cells in the absence of innervation) expressed the STO MyHC particularly when they developed in a spatial relation to nuclear bag fibres.
Soukup
T
T
Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic. tmsoukup@biomed.cas.cz
Jirmanová
I
I
Mrácková
K
K
Zacharová
G
G
Thornell
L E
LE
D000818:Animals; D000831:Animals, Newborn; D003714:Denervation; D004525:Efferent Pathways; D006614:Hindlimb; D024510:Muscle Development; D018485:Muscle Fibers, Skeletal / Q000166:cytology / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000254:growth & development / Q000294:innervation / Q000378:metabolism; D018995:Myosin Heavy Chains / Q000378:metabolism*; D020033:Protein Isoforms / Q000378:metabolism; D051381:Rats
D020033:Protein Isoforms; D018995:Myosin Heavy Chains