FUNCTIONAL-EVALUATION OF REGENERATED AND MISROUTED AXONS TO GLABROUS AND HAIRY SKIN OF THE RAT HIND FOOT AFTER SCIATIC NEUROTOMY AND SUTURE

The function of misrouted regenerated polymodal nociceptor C-fibers an d low-threshold mechanoreceptive axons in the lateral plantar nerve (L PN) and in the foot branch of the superficial peroneal nerve (fSPN) wa s evaluated 3 months after unilateral sciatic neurotomy and suture. Tw o weeks before evaluation the tibial fascicle (or the peroneal fascicl e) above the neurotomy was cut and tied off. In this way only function al regeneration of misrouted axons was tested in the LPN (or the fSPN) . In regenerated animals the glabrous skin area had no functional fSPN -related low-threshold mechanoreceptive axons. However, the hairy fSPN skin area showed function of misrouted LPN-related low-threshold mech anoreceptive axons. In both the glabrous skin domain innervated by the LPN and the hairy skin area supplied by the fSPN, functional regenera tion of misrouted polymodal nociceptor C-fibers was found. We conclude that functional regeneration of misrouted axons related to polymodal nociceptive units and low-threshold mechanoreceptive units is more eff icient in hairy skin of the rat foot whereas only misrouted polymodal nociceptor C-fibers recover function in glabrous skin. (C) 1995 Academ ic Press, Inc.