Nerve growth factor receptor-like immunoreactivity in nerve fibers in the spinal and medullary dorsal horn of the adult monkey and cat: correlation with calcitonin gene-related peptide-like immunoreactivity.

The distribution of nerve growth factor receptor (NGFr)-like immunoreactivity and of calcitonin gene-related peptide (CGRP)-like immunoreactivity was studied in nerve fibers of the spinal and medullary dorsal horn of the monkey and the cat, using double-labelling immunohistochemistry with polyclonal CGRP antiserum and a monoclonal antibody against human NGFr. In both species there was an extensive distribution overlap between NGFr-LI and CGRP-LI. However, lack of NGFr-LI in many CGRP-immunoreactive axons suggests that not all CGRP-positive primary afferent fibers possess NGFr.