ELECTRICAL-STIMULATION OF THE SCIATIC-NERVE ALTERS NEUROPEPTIDE CONTENT AND LYMPHOCYTE MIGRATION IN THE SUBCUTANEOUS TISSUE OF THE RAT HINDPAW

To study the possible mechanism by which peripheral nerves mediate imm une responses in target tissues, electrical stimulation of the sciatic nerve was combined with subcutaneous microdialysis of the hind paw. F ollowing unilateral stimulation of the sciatic nerve, an ipsilateral r ise in substance P and a bilateral rise in VIP levels were observed in dialysate samples from experimental us control animals. Electrical st imulation of the sciatic nerve induced a marked hyperemia and swelling of the ipsilateral paw. Quantitative immunocytochemical analysis of p araffin-embedded sections of the hind foot pads demonstrated T lymphoc yte migration ipsilateral to the stimulated nerve. These findings sugg est that peripheral nerves can directly modulate local immune and infl ammatoryresponses.