Figure 5. Regeneration of rat sciatic nerve after neurolytic N-pentyl tetracaine injection. (A) Control sciatic nerve (toluidine blue stain; magnification, x520). (B) Sciatic nerve 14 days after injection of N-propyl tetracaine (37 mM; toluidine blue stain; magnification, x520). (C) Sciatic nerve 48 days after injection of N-pentyl tetracaine (37 mM). Some degenerating fibers and small-caliber (regenerating) fibers are present (toluidine blue stain; magnification, x520). (D) Sciatic nerve 68 days after injection of N-pentyl tetracaine (37 mM). Degenerating fibers are fewer than at 48 days, and small-caliber (regenerating) fibers are more abundant (toluidine blue stain; magnification, x520). (E) Control sciatic nerve. The overall axonal population is very uniform (toluidine blue stain; magnification, x260). (F) Sciatic nerve 68 days after injection of N-pentyl tetracaine (37 mM). There is a tendency for the small-caliber (regenerating) fibers to be most abundant adjacent to the perineurium (toluidine blue stain; magnification, x260)