Vesicular acetylcholine transporter can be a morphological marker for the reinnervation to muscle of regenerating motor axons.
This study was designed to evaluate whether the vesicular acetylcholine transporter (VAChT), which packages acetylcholine into synaptic vesicles, can be used as a marker for regenerating motor axon terminal. We examined motor axon regeneration in the tongue after hypoglossal nerve axotomy, using an anterograde tracer biotin-dextran (BD), retrograde tracer Fluoro-Gold (FG), electron microscopic (EM) observation, and VAChT immunocytochemistry. BD study demonstrated that outgrowth of thin regenerating axons into the frontal area of the tongue was firstly observed at 14 post-operative days, and presynaptic formation of neuromuscular junction (NMJ) was observed from 21 post-operative days. Under electron microscopic observation, reconstruction of new NMJs was observed within the interval between 21 and 28 days. VAChT-immunoreactive nerve terminals disappeared by 3 days after axotomy, slightly appeared at 14 post-operative days, and thereafter gradually increased in number from 21 to 28 post-operative days. The re-expression of VAChT positive presynaptic terminal was almost the same as those obtained in BD, FG and EM studies. Regenerating axons tip in the crush model of the hypoglossal nerve exhibited prominent VAChT immunoreactivity in growing tip of regenerating axons. These indicate that VAChT is an excellent morphological indicator for regenerating nerve terminals of motor neurons.
Maeda
Mitsuyo
M
Departments of Anatomy and Neurobiology, Graduate School of Medicine, Osaka City University, 1-4-3 Asahimachi, Abeno-ku, Osaka 545-8585, Japan.
Ohba
Norihiro
N
Nakagomi
Saya
S
Suzuki
Yasuhiro
Y
Kiryu-Seo
Sumiko
S
Namikawa
Kazuhiko
K
Kondoh
Wataru
W
Tanaka
Akemi
A
Kiyama
Hiroshi
H
D000818:Animals; D001369:Axons / Q000378:metabolism*; D019771:Axotomy / Q000379:methods; D015415:Biomarkers / Q000032:analysis; D001710:Biotin / Q000031:analogs & derivatives* / Q000378:metabolism; D002038:Bungarotoxins / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism*; D003911:Dextrans / Q000378:metabolism; D005456:Fluorescent Dyes / Q000378:metabolism; D007839:Functional Laterality; D061228:Hypoglossal Nerve Injuries; D007150:Immunohistochemistry / Q000379:methods; D008297:Male; D026901:Membrane Transport Proteins; D008854:Microscopy, Electron; D009132:Muscles / Q000294:innervation* / Q000378:metabolism; D009409:Nerve Crush / Q000379:methods; D009416:Nerve Regeneration / Q000502:physiology*; D009469:Neuromuscular Junction / Q000648:ultrastructure; D051381:Rats; D017208:Rats, Wistar; D013266:Stilbamidines / Q000378:metabolism; D013997:Time Factors; D014059:Tongue / Q000648:ultrastructure; D050494:Vesicular Acetylcholine Transport Proteins; D033921:Vesicular Transport Proteins
C049774:2-hydroxy-4,4'-diamidinostilbene, methanesulfonate salt; D015415:Biomarkers; D002038:Bungarotoxins; D002352:Carrier Proteins; D003911:Dextrans; D005456:Fluorescent Dyes; D026901:Membrane Transport Proteins; C493461:Slc18a3 protein, rat; D013266:Stilbamidines; D050494:Vesicular Acetylcholine Transport Proteins; D033921:Vesicular Transport Proteins; C076397:biotinylated dextran amine; D001710:Biotin