Fig. 1.

Immunocytochemistry and size-based discrimination of neuronal subtypes. A and B: CGRP-positive cells (blue) indicate peptidergic C-fiber neurons (C Pep). Isolectin B4 (IB4)-positive (green), Neurofilament 200 (NF200)-negative cells indicate nonpeptidergic C-fiber neurons (C Non-pep). IB4-positive, NF200-positive (red) cells indicate Aδ-fiber neurons. NF200 (only)-positive cells indicate Aβ-fiber neurons. Scale bar represents 200 µm. C: automated measurements of cross-sectional area suggest a large percentage of small- and medium-gauge neurons, indicating a primarily nociceptive cell population.