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

1991 ◽  
Vol 69 (11) ◽  
pp. 1769-1773 ◽  
Author(s):  
H. A. Tissenbaum ◽  
D. J. Parry

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.Key words: mouse, tibialis anterior muscle, partial denervation, motorneuron size.

1996 ◽  
Vol 126 (1) ◽  
pp. 266-272 ◽  
Author(s):  
Daniel Taillandier ◽  
Charles-Yannick Guezennec ◽  
Philippe Patureau-Mirand ◽  
Xavier Bigard ◽  
Maurice Arnal ◽  
...  

2015 ◽  
Vol 118 (5) ◽  
pp. 613-623 ◽  
Author(s):  
Irina V. Ogneva ◽  
V. Gnyubkin ◽  
N. Laroche ◽  
M. V. Maximova ◽  
I. M. Larina ◽  
...  

Altered external mechanical loading during spaceflights causes negative effects on muscular and cardiovascular systems. The aim of the study was estimation of the cortical cytoskeleton statement of the skeletal muscle cells and cardiomyocytes. The state of the cortical cytoskeleton in C57BL6J mice soleus, tibialis anterior muscle fibers, and left ventricle cardiomyocytes was investigated after 30-day 2- g centrifugation (“2- g” group) and within 12 h after its completion (“2- g + 12-h” group). We used atomic force microscopy for estimating cell's transverse stiffness, Western blotting for measuring protein content, and RT-PCR for estimating their expression level. The transverse stiffness significantly decreased in cardiomyocytes (by 16%) and increased in skeletal muscles fibers (by 35% for soleus and by 29% for tibialis anterior muscle fibers) in animals of the 2-g group (compared with the control group). For cardiomyocytes, we found that, in the 2- g + 12-h group, α-actinin-1 content decreased in the membranous fraction (by 27%) and increased in cytoplasmic fraction (by 28%) of proteins (compared with the levels in the 2- g group). But for skeletal muscle fibers, similar changes were noted for α-actinin-4, but not for α-actinin-1. In conclusion, we showed that the different isoforms of α-actinins dissociate from cortical cytoskeleton under increased/decreased of mechanical load.


2016 ◽  
Vol 116 (4) ◽  
pp. 1848-1858 ◽  
Author(s):  
Ryan M. Peters ◽  
Monica D. McKeown ◽  
Mark G. Carpenter ◽  
J. Timothy Inglis

Age-related changes in the density, morphology, and physiology of plantar cutaneous receptors negatively impact the quality and quantity of balance-relevant information arising from the foot soles. Plantar perceptual sensitivity declines with age and may predict postural instability; however, alteration in lower limb cutaneous reflex strength may also explain greater instability in older adults and has yet to be investigated. We replicated the age-related decline in sensitivity by assessing monofilament and vibrotactile (30 and 250 Hz) detection thresholds near the first metatarsal head bilaterally in healthy young and older adults. We additionally applied continuous 30- and 250-Hz vibration to drive mechanically evoked reflex responses in the tibialis anterior muscle, measured via surface electromyography. To investigate potential relationships between plantar sensitivity, cutaneous reflex strength, and postural stability, we performed posturography in subjects during quiet standing without vision. Anteroposterior and mediolateral postural stability decreased with age, and increases in postural sway amplitude and frequency were significantly correlated with increases in plantar detection thresholds. With 30-Hz vibration, cutaneous reflexes were observed in 95% of young adults but in only 53% of older adults, and reflex gain, coherence, and cumulant density at 30 Hz were lower in older adults. Reflexes were not observed with 250-Hz vibration, suggesting this high-frequency cutaneous input is filtered out by motoneurons innervating tibialis anterior. Our findings have important implications for assessing the risk of balance impairment in older adults.


2015 ◽  
Vol 11 (4) ◽  
pp. 332-334
Author(s):  
AS Hegde

A muscle hernia is defined as a protrusion of the muscle belly through an acquired or congenital fascial defect. Muscle herniation through fascia is a relatively rare entity. Though predominantly asymptomatic, rarely they can be cause of vague pain in the leg, aggravated by exercises. Various conservative measures have been described for asymptomatic hernias, but treatment of symptomatic cases remains controversial. Here we present a case of symptomatic post traumatic tibialis anterior muscle herniation which was treated successfully with autologous fascia lata graft in Yenepoya Medical College, Mangalore in the month of January 2013.Muscle hernias should be kept in mind as a rare differential diagnosis whenever patients present with persisting vague leg pain with or without swelling. If conservative treatment fails, we recommend closure with autologous graft or fasciotomy to relieve the symptoms.Kathmandu Univ Med J 2013; 11(4): 332-334


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