Increase of CGRP expression in motor endplates within fore and hind limb muscles of the degenerating muscle mouse (Scn8a(dmu)).
The distribution of calcitonin gene-related peptide (CGRP) was examined in skeletal muscles of fore and hind limb as well as in oral and cranio-facial regions of the degenerating muscle (dmu) mouse, which harbours a null mutation in the voltage-gated sodium channel gene Scn8a. In limb, oral and cranio-facial muscles of wild type mice, only a few motor endplates contained CGRP-immunoreactivity. However, many CGRP-immunoreactive motor endplates appeared in the triceps brachii muscle, the biceps brachii muscle, the brachialis muscle, and the gastrocnemius muscle of dmu mice. CGRP-immunoreactive density of motor endplates in the skeletal muscles was also elevated by the mutation. In these muscles, the atrophy of muscle fibers could be detected and the density of cell nuclei in the musculature increased. In the flexor digitorum profundus muscle, the flexor digitorum superficialis muscle, and the soleus muscle as well as in oral and craniofacial muscles, however, the distribution of CGRP-immunoreactivity was barely affected by the mutation. The morphology of muscle fibers and the distribution of cell nuclei within them were also similar in wild type and dmu mice. In the lumbar spinal cord of dmu mice, CGRP-immunoreactive density of spinal motoneurons increased. These findings suggest that the atrophic degeneration in some fore and hind limb muscles of dmu mice may increase CGRP expression in their motoneurons.
Tadasu
T
Sato
Yoshinaka
Y
Shimizu
Mitsuhiro
M
Kano
Toshihiko
T
Suzuki
Hiroyasu
H
Kanetaka
Leona W G
LW
Chu
Patrice D
PD
Côté
Hidetoshi
H
Shimauchi
Hiroyuki
H
Ichikawa
D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000235:genetics* / Q000378:metabolism; D005552:Forelimb / Q000378:metabolism* / Q000473:pathology; D015870:Gene Expression; D006614:Hindlimb / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009045:Motor Endplate / Q000235:genetics* / Q000378:metabolism; D009046:Motor Neurons / Q000378:metabolism / Q000473:pathology; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000473:pathology; D009133:Muscular Atrophy / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D062557:NAV1.6 Voltage-Gated Sodium Channel; D009419:Nerve Tissue Proteins / Q000235:genetics; D015222:Sodium Channels / Q000235:genetics; D015854:Up-Regulation
D062557:NAV1.6 Voltage-Gated Sodium Channel; D009419:Nerve Tissue Proteins; C491046:Scn8a protein, mouse; D015222:Sodium Channels; D015740:Calcitonin Gene-Related Peptide