The effect of partial denervation of tibialis anterior (TA) muscle on the number and sizes of motorneurons in TA motornucleus of normal and dystrophic (C57BL dy2j/dy2j) mice.
The tibialis anterior (TA) muscle in one leg of normal (C57BL) and dystrophic (dy2j) mice was partially denervated by resection of a part of the lateral popliteal nerve. Two months later the muscle was injected with horseradish peroxidase to permit visualization of the motorneurons that survived. Partial denervation in both C57 and dy2j mice resulted in reduction of the number of motorneurons that supplied the muscle to approximately one-half the normal complement. The surviving motorneurons were found to be significantly larger (about 25%) than their contralateral counterparts. This condition persisted up to 18 months and is not considered to be a transient response to the trauma associated with the partial denervation. When the size of the target tissue was also reduced by extirpation of one-half of TA together with partial denervation, motorneuron size was not found to increase. It is suggested that the increase in size is a response to the metabolic demands placed upon the motorneuron by an increase in the size of the motor unit.
Tissenbaum
H A
HA
Department of Physiology, University of Ottawa Faculty of Medicine, Ont., Canada.
Parry
D J
DJ
D000818:Animals; D002452:Cell Count; D006614:Hindlimb; D006735:Horseradish Peroxidase; D051379:Mice; D008810:Mice, Inbred C57BL; D009046:Motor Neurons / Q000166:cytology* / Q000502:physiology; D009121:Muscle Denervation; D009132:Muscles / Q000294:innervation*; D009137:Muscular Dystrophy, Animal / Q000473:pathology*
D006735:Horseradish Peroxidase