Immunohistochemical identification of the pacemaker cajal cells in the normal human vagina

Objectives: It is claimed that the electric waves recorded from the gut and urinary system are generated from specialized cells called interstitial cells of Cajal (ICCs). As the vagina exhibits electric activity, we investigated the hypothesis that ICCs could be detected in its wall. Methods: Vaginal specimens were obtained from 28 female cadavers (mean age 34.8±10.8 SD years) and fixed sections were prepared for immunohistochemical investigations using the specific ICC marker c-kit. Controls for antisera specificity consisted of tissue incubated with normal rabbit serum substituted for the primary antiserum. Results: Branching, c-kit-positive ICC-like cells were found in the muscular layer of the vagina. They were clearly distinguishable from the smooth muscle cells which were c-kit negative and not branched and from the c-kit positive non-branched mast cells. Immunoreactivity was absent in the negative controls. Conclusions: We have, for the first time, identified in the vagina ICCs that may be responsible for initiating the slow waves recorded from the vaginal smooth muscle cells.