AMINERGIC AND PEPTIDERGIC INNERVATION OF THE BILIARY PATHWAY OF THE CAT

The course and distribution of different neuropeptide-containing nerve elements were studied using immunohistochemistry. The distribution an d density of peptide-containing fibres were compared with tyrosine hyd roxylase (TH) and dopamine-beta-hydroxylase (DBH) immunoreactivity in the wall of the biliary pathway. Many immunoreactive nerve fibres were found in all layers of the gallbladder and in the common hepatopancre atic duct. Some immunoreactive nerve fibres were observed close to the epithelial lining, and to the smooth muscle cells. The TH- and DBH-im munoreactive nerve fibres were mainly observed in the liver and around blood vessels. Some nerve cell bodies immunoreactive to neuropeptide Y, somatostatin and substance P were also observed in the muscle layer of the gall bladder. The distribution and the close relation between the effector cells and the peptide-containing nerve fibres suggest tha t these neuropeptides might have important role in the motility, chang es of the absorption and secretion of the gall bladder, and the biliar y pathway. The TH- and DBH immunoreactive nerves have an important rol e in the brood supply of the biliary pathway.