Retrograde Effect of Muscle on Forms of Acetylcholinesterase in Peripheral Nerves

Abstract

In the peripheral nerves of birds and mammals, acetylcholinesterase (AChE) exists in four main molecular forms (G1, G2, G4, and A12). The two heaviest forms (G4 and A12) are carried by rapid axoplasmic transport, whereas the two lightest forms (G1 and G2) are probably much more slowly transported. Here we report that nerves innervating fast-twitch (F nerves) and slow-twitch (S nerves) muscles of the rabbit differ both in their AChE molecular form patterns and in their anterograde and retrograde axonal transport parameters. Since we had previously shown a selective regulation of this enzyme in fast and slow parts of rabbit semimembranosus muscle, we wondered whether the differences observed in the nerve could be affected by the twitch properties of muscle. The results reported here show that in F nerves that reinnervate slow-twitch muscles, both the AChE molecular form patterns and axonal transport parameters turn into those of the S nerve. These data suggest the existence of a retrograde specific effect exerted by the muscles on their respective motoneurons.

Expression of specific white adipose tissue genes in denervation‐induced skeletal muscle fatty degeneration

“…This contrasts with the slower and incomplete transformation of the slow‐twitch SMp. In fact, the SMp still contains numerous muscles fibers surrounded by adipose cells 1 year after denervation [22]. Thus, muscles constituted by fast muscle fibers are the most affected by denervation.…”

Regulation by exercise of the pool of G4 acetylcholinesterase characterizing fast muscles: opposite effect of running training in antagonist muscles

“…Nonetheless, taking into account the matching of the G, content of the motor nerves with that of their muscles (Gisiger and Stephens, 1982-l 983, 1984Bacou et al, 1985), together with the mirrored AChE changes exhibited by the trained antagonist muscles, the absence of an effect of training on sciatic nerve AChE was not unanticipated. Indeed, if, as one would expect, training induced in the motor nerves opposite G, changes parallel to those in their respective muscles (increase in extensors versus decrease in flexors), then these mirrored modifications are likely to mutually offset one another when AChE is measured at the level of the sciatic nerve trunk.…”

Expression of Myosin Isoforms in Denervated, Cross‐Reinnervated, and Electrically Stimulated Rabbit Muscles

“…The cross-reinnervation experiment was carried out on SMp muscle only, since the opposite operation is made unreliable owing to the large size of SMa muscle and the short length of SMp nerve. Cross-reinnervation was performed bilaterally on slow-twitch SMp of one-week-old rabbits according to Bacou et al (1985). Briefly, the original nerve branch innervating the SMp was sectioned, twice ligated and reflected backwards to prevent reinnervation.…”