[Distribution and structural organization of autonomic neural apparatus of the rat pancreas (an immunohistochemical study)].

Using the immunohistochemical methods for detection of neurofilaments (NF), peripherin (PRF), synaptophysin (SF), tyrosine hydroxylase (TH) and Nissl-staining with toluidine blue, thick sections (10-20 microm) prepared through all parts of pancreas of adult Wistar rats (n=7) were studied. The topography and the density of distribution of pancreatic islets in the various parts of pancreas were defined. The greatest density of the islets was found in the body of pancreas. The dense innervation of the organ was detected which included several nervous plexuses: the big-looped one consisting of nervous bundles and small trunks of NF-positive myelinated and unmyelinated nervous fibers, the second one was formed by PRF-positive thin posganglionic bundles of axons and microganglia, and the third one, detected with SF-staining, was main terminal plexus consisting of varicose axons with en passant synapses. Interactions of synaptophysin-positive terminals (distant en passant synapses) with blood vessels, endocrine (islet) and exocrine cells, excretory ducts of the pancreatic lobules are described in details. Peculiarities of the structure of parasympathetic ganglia, their neurons, and pericellular synaptic apparatus are described; problems of the innervation and the nature of pancreatic insular endocrine cells are discussed. Attention is drawn to the fact that in no case neurons were found in the islets in the rat pancreas.