[Neuropeptide-containing nerve fibers in the gallbladder]

With the use of different antisera and Avidin-Biotin-Peroxidase technique, several immunopositive nerve fibers were observed in the wall of the gallbladder of the cat. A large amount of neuropeptide Y, substance P, somatostatin, vasoactive intestinal polypeptide immunoreactive nerve fibers were found in all layers. The most numerous of neuropeptide was the neuropeptide Y. Some immunoreactive nerve cell bodies (neuropeptide Y, substance P, somatostatin) were also observed in the muscle layers. Only a few calcitonin gene-related peptide positive were found in the wall. Cholecystokinin immunoreactive nerve fibers were observed very rarely and were located only in the muscle layers. Enkephalin positive nerve fibers were not found. Under the electron-microscope these immunoreactive nerve fibers were observed in a very close situation to the epithelial lining, to the smooth muscle cells. There were some immunoreactive nerve fibers around the smooth muscle cells of the arterioles and arteries. The distribution and the situation on the effector cells it is supposed that these neuropeptides might have important role in the motility, in the changes of the absorption and secretion of the gallbladder.