Distribution of different neuropeptides in the rat urinary bladder

The presence and distribution of the neuropeptides VIP (vasoactive intestinal polypeptide), NPY (neuropeptide tyrosine), SP (substance P), GAL (galanin), SST-14 (somatostatin-14) and SST-28 (somatostatin-28), were investigated in the rat urinary bladder by light microscopy immunohistochemistry. The peptides were essentially present in the fundus and corpus of the bladder wall, in particular in the muscle coat. NPY and VIP were most readily detected, and were sometimes co-localized in the muscle layer and around many blood vessels, SP was present essentially in the submucosa, and GAL in the muscle layer. SST was observed, albeit rarely, at the base of the urinary bladder: only SST-14 was present in the muscle layer; SST-28 was not revealed by immunohistochemistry.