Neuronal NOS immunohistochemical staining of the paracervical ganglion from WT and nNOS−/− female mice. Serial sections from the uterocervical junction are shown. In the WT female, nNOS is localized in the ganglion cells and nerve fibers (A). Conversely, preincubation of nNOS antiserum with nNOS peptide abolishes immunoreactivity (C). In the nNOS−/− female, tissue incubated with nNOS antiserum reveals only nonspecific background staining (B) even though nerve localizations are confirmed with synaptophysin antibody (D). Scale bars, 250 µm.