CGRP-immunoreactive nerves in the genitalia of the female rat originate from dorsal root ganglia T11-L3 and L6-S1: a combined immunocytochemical and retrograde tracing study.

The origin of the calcitonin gene-related peptide (CGRP)-immunoreactive nerve fibres in the genital organs of the female rat was investigated by immunocytochemistry and retrograde tracing with the fluorescent dye True blue. The tracing results revealed that these tissues receive an afferent nerve supply from two separate groups of dorsal root ganglia: T11-L3 and L6-S1. In T11-L3 ganglia 66-86% of True blue-labelled neurones displayed CGRP immunoreactivity whilst 45-63% of labelled cells in L6-S1 ganglia contained the peptide. The results indicate that CGRP-containing dorsal root ganglion neurones form a major part of the afferent sensory nerve supply to the female rat genitalia.