TY  - JOUR
A1  - ,  
T1  - Site-dependent difference in the density of sympathetic nerve fibers in muscle-innervating nerves: a histologic study using human cadavers
JO  - Eur. J. Anat.
SN  - 1136-4890
Y1  - 2012
VL  - 16
SP  - 33
EP  - 42
UR  - http://www.eurjanat.com/web/paper.php?id=120004tn
KW  - Tyrosine hydroxylase-positive nerve fibers
KW  - Sympathetic innervation
KW  - Striated muscles
KW  - Feeding artery
KW  - Muscle hilus
N2  - The autonomic nerve supply of skeletal muscle has become a focus of interest because it is closely related to the adaptation of energy metabolism with aging. However, there is no comprehensive information concerning the sympathetic nerves present in muscle-innervating nerves (muscle-nerve). At the point of entry of muscle-nerves into 8 striated muscles (the soleus, extensor carpi radialis, infraspinatus, genioglossus, extra- ocular medial rectus, temporalis, lateral pterygoid, and digastricus anterior belly) in 15 cadavers of elderly people, we counted both tyrosine hydroxylasepositive nerve fibers (TH- fibers) and motor nerve fibers to estimate the ratio of THfiber/ motor fibers. The 3 limb muscles were found to have a high ratio (soleus, 58%; infraspinatus; 45%; extensor, 36%), whereas the 4 head muscles (digastricus, 23%; genioglossus, 15%; temporalis, 10%; lateral pterygoid, 6%; medial rectus, 1%) had relatively low ratios. The site- dependent characteristics of the THfibers seemed to reflect their commitment to muscle activity. However, some discrepant characteristics were noted: 1) In spite of the tonic and continuous activity required for both the genioglossus and infraspinatus, the proportions of TH-fibers were quite different between the tongue and the shoulder muscles; 2) Likewise, the soleus and extra-ocular rectus showed a considerable difference, even though rapid and phasic contraction is essential for both muscles. Rather than reflecting the influence of postnatal functional demand, these site- dependent characteristics might develop as a result of differences in sympathetic innervation of the striated muscles during fetal development, i.e., a short course along the arteries feeding the head muscles, or a long course along the muscle-nerves to the limb muscles.
ER  -