Fig. 4.

Densitometry of P2X3 and calcitonin-gene-related peptide (CGRP) immunoreactive neurons in prenatal human DRG from 4 to 8 gestational months. The average density of P2X3 immunoreactive cells is 322.8 ± 10.06, 303.76 ± 7.38, 269.48 ± 11.12, 246.3 ± 8.25, and 205.52 ± 5.45 cells/mm² at 4, 5, 6, 7, and 8 gestational months, respectively. The average density of CGRP immunoreactive cells is 29.84 ± 9.47, 33.2 ± 4.79, 47.12 ± 11.09, 62.16 ± 7.67, and 73.36 ± 13.67 at the above age points, respectively. One-way ANOVA analysis for P2X3 (P < 0.01, F = 15.23, df = 5, 11) and CGRP (P < 0.01, F = 11.26, df = 5, 11) cells shows statistically significant difference among groups at the above ages