Journal of Neurophysiology, Vol 40, Issue 4 791-799, Copyright © 1977 by APS
Fast-conducting skeletofusimotor axons supplying intrafusal chain fibers in the cat peroneus tertius muscle
D. W. Harker, L. Jami, Y. Laporte and J. Petit
1. In six experiments on cat peroneus tertius muscle, from 12 to 23 motor
axons with conduction velocities above 85 m/s were repetitively stimulated
so as to produce glycogen depletion in the muscle fibers they innervated.
2. The whole muscle was then quick-frozen, serially cut, stained to
demonstrate glycogen, and examined for intrafusal glycogen depletion. 3.
Zones of glycogen depletion were found in 27 of the 99 examined spindles:
they were almost invariably located on chain fibers and specifically on the
longest of the chain fibers in affected spindles. 4. Since it was shown
that there are no purely fusimotor fast axons in the motor supply to
peroneus tertius, it is concluded that skeletofusimotor axons are present
among the fastest motor axons to this muscle.
