Fig. 3. Cell diameter distribution of neurons immunostaining for somatostatin, calcitonin gene–related peptide (CGRP), P2X3 receptor, transient receptor potential vanilloid type 1 (TRPV1), and fluorogold. The average diameter of fluorogold-labeled neurons is significantly larger than those untraced cells stained for each antibody (  P < 0.001 compared among groups).