Nerve control of type 2A MHC isoform expression in regenerating slow skeletal muscle.
Bupivacaine-induced regeneration was studied in rat soleus muscle under several conditions, with the focus on type 2A and type 1 myosin heavy chain (MHC) isoform expression. In denervated muscles, type 1 was absent, whereas type 2A was widely expressed, a pattern of regeneration which appeared to be independent of fibrillation activity of the muscle. Both type 1 and type 2A isoforms were absent in muscles regenerated during tetrodotoxin (TTX) block of impulse conduction in the sciatic nerve, but type 2A was still present when the TTX block was associated with the vinblastine block of axoplasmic flow; vinblastine block alone caused the coexpression of type 1 and type 2A isoforms in the majority of fibers. These results suggest that axoplasmic flow carries some chemical factor that inhibits 2A MHC isoform expression. The results are also of clinical interest, contributing to the understanding of factors controlling muscle differentiation and adaptation.
Megighian
A
A
Department of Human Anatomy and Physiology, Section of Physiology, University of Padua, Via Marzolo 3, 35131 Padova, Italy.
Germinario
E
E
Rossini
K
K
Midrio
M
M
Danieli-Betto
D
D
D000779:Anesthetics, Local / Q000494:pharmacology; D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D001370:Axonal Transport / Q000187:drug effects; D002045:Bupivacaine / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D005207:Fasciculation / Q000188:drug therapy; D005260:Female; D007150:Immunohistochemistry; D008297:Male; D009121:Muscle Denervation; D018657:Muscle Fibers, Slow-Twitch / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D018482:Muscle, Skeletal / Q000187:drug effects / Q000294:innervation* / Q000378:metabolism* / Q000473:pathology; D018995:Myosin Heavy Chains / Q000096:biosynthesis*; D011342:Procainamide / Q000494:pharmacology; D020033:Protein Isoforms; D051381:Rats; D017208:Rats, Wistar; D012038:Regeneration / Q000187:drug effects / Q000502:physiology; D012584:Sciatic Nerve / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure; D013779:Tetrodotoxin / Q000494:pharmacology; D014747:Vinblastine / Q000494:pharmacology
D000779:Anesthetics, Local; D000972:Antineoplastic Agents, Phytogenic; D020033:Protein Isoforms; D013779:Tetrodotoxin; D014747:Vinblastine; D018995:Myosin Heavy Chains; D011342:Procainamide; D002045:Bupivacaine