Light,fluorescence and electron microscopic studies on “neurosecretion” in tritonia diomedia bergh (Mollusca,Nudibranchia)

Summary Membrane-limited electron-dense inclusions designated as elementary neurosecretory granules have a characteristic distribution in cerebropleural ganglia of the nudibranch snail Tritonia diomedia. They occur in the neuropile and also in individual nerve fibres, connectives and commissures. These granules have been found neither in perikarya of nerve cells nor in proximal segments of their processes.Specific fluorescence obtained in Tritonia preparations with Sterba's pseudoisocyanin method for neurosecretory products has the same pattern of location.The distribution of stainable material in preparations prepared with ordinary neurosecretory procedures (chrome haematoxylin-phloxin after Gomori-Bargmann and paraldehydefuchsin after Gomori-Gabe) is similar to that described by different authors in other gastropods, but strongly differs from the locationof elementary neurosecretory granules and of pseudoisocyanin-positive material. The adequacy of different histological methods for studying neurosecretion in gastropods is discussed.