S-100-immunoreactive nerves in the urinary bladder of the rat

The innervation of the rat urinary bladder was investigated by light microscopy with use of S-100 antiserum and the peroxidase-antiperoxidase immunohistochemical technique according to Sternberger. The S-100 protein, a marker for myelinated nervous fibers, was mostly present in the muscle coat and the adventitia at the base of the bladder. Myelinated fibers were not observed in the epithelial layer, nor were ganglia found in the bladder wall. No differences in the amount and distribution of nerve fibers were found in full and empty bladders. Results were correlated with the analysis of the whole nervous component conducted by Ag staining according to Linder.