Ultrastructural detection of granulated cells in the autonomic ganglia of the rat pancreas.

Electron microscopic examination of the intrinsic autonomic ganglia of the rat pancreas revealed the presence of small cells, when compared to the principal ganglionic neurons, within a particular type of ganglia. The small cells were often located in clusters around fenestrated capillaries, but their most striking characteristic was the presence of catecholamine-like granules distributed throughout the cytoplasm. The possible implication of this new source of catecholamines, acting either as interneurons or as neuroendocrine cells, is discussed in the light of a local regulatory mechanism for islet secretion.