PEPTIDES AND NEUROMAS - CALCITONIN-GENE-RELATED PEPTIDE, SUBSTANCE-P,AND MAST-CELLS IN A MECHANOSENSITIVE HUMAN SURAL NEUROMA

We examined and compared a mechanosensitive human sural neuroma and a contralateral sural nerve collected simultaneously from a patient invo lved in a diabetic neuropathy research protocol. Using indirect immuno fluorescence staining, we identified a striking difference in the cont ent within axons of two neuropeptides, substance P (SP) and calcitonin gene-related peptide (CGRP), between the contralateral nerve and the neuroma. Unlike the contralateral nerve, where immunofluorescence was sparse, a significant number of disorganized axon profiles that staine d brightly positive for CGRP or SP were identified in the neuroma. In contrast, staining for tyrosine hydroxylase, a label of sympathetic ax ons, was largely absent except around one large arteriole. The neuroma specimen also contained large numbers of serotonin-containing mast ce lls, only noted occasionally in the contralateral nerve. The peptide s taining and mast cell accumulation in the human neuroma closely resemb led changes we have previously observed in an animal neuroma model. Lo cal neuropeptides may play a role in the injury response of peripheral nerve, and may be related to mechanosensitivity. (C) 1997 John Wiley & Sons, Inc.