GAP-43 PERSISTS IN ADULTHOOD AND COEXISTS WITH SP AND CGRP IN HUMAN TRIGEMINAL SENSORY NEURONES

IMMUNOHISTOCHEMISTRY was used to examine the occurrence and colocaliza tion of the growth-associated protein GAP-43 with substance P (SP) and calcitonin gene-related peptide (CGRP) in the human trigeminal gangli on and sensory nucleus at perinatal and adult life stages. The results obtained show that: GAP-43-like immunoreactive (LI) material persists in trigeminal primary sensory neurones of the normal adult; the GAP-4 3-LI ganglionic population partially overlaps with those immunoreactiv e to SP and CGRP; the distribution pattern of the protein in the spina l nucleus varies with age; in the adult subnucleus caudalis GAP-43 is co-distributed with SP and CGRP. It is suggested that the trigeminal G AP-43-LI neuronal system may retain the capacity for structural and fu nctional plasticity in adult life.