It has been shown that the adult mammalian CNS is capable of axonal sprouting and limited regeneration in response to injury, but this regeneration is interrupted by the scar produced in the lesioned area by proliferating glia. Experiments by Barnes and Worrall (1) demonstrated that the proximal stump of a ventral root when grafted to a ganglionectomized dorsal root is capable of reinnervating the spinal cord without interference by the glia, and is capable of forming new functional synapses within the spinal cord. In an effort to provide anatomical verification for this physiological study, we repeated their experimental procedure. A transmission electron microscopic investigation of the spinal cord where the dorsal roots terminate was undertaken in an attempt to identify these reinnervating axons and newly formed synapses. Regeneration time was varied from 8 to 16 weeks. In order to identify reinnervating from normal tissue, the graft was lesioned 3 or 4 days prior to preparation of the spinal cord for electron microscopy.
Transmission Electron Microscopic Investigation of Bainites in Ag-27.6 wt%Zn Alloy