Innervation of the human vaginal mucosa as revealed by PGP 9.5 immunohistochemistry

In order to obtain a description of the innervation of the vaginal wall we employed an antiserum against the general neuronal marker, protein gene product 9.5, on normal human vaginal mucosa. Specimens were taken from the anterior and posterior fornices, from the anterior vaginal wall at the bladder neck level and from the introitus vaginae region, and then processed for indirect immunohistochemistry. All regions studied revealed a profound innervation, although regional differences were noted. The more distal areas of the vaginal wall had more nerve fibers compared to the more proximal parts. Also, biopsies from the anterior wall generally were more densely innervated than the posterior wall. Some large nerve coils were observed in lamina propria of the anterior wall as well as gatherings of thick-walled medium-sized blood vessels. Free intraepithelial nerve endings were only detected in the introitus vaginae region. These fibers were very thin, always varicose and could be observed just a few cell layers from the surface. In this part of the vagina, protein gene product 9.5 antibodies also stained cells within the basal parts of the epithelium. These cells were also neurone-specific enolase positive and resembled, from a morphological point of view, Merkel cells.