The terminal autonomic nervous system in the pancreas of newts. Electron microscopic investigations using acetylcholinesterase and zinc iodide-osmium tetroxide reactions.

The intrinsic innervation in the pancreas of newts Triturus vulgaris, Tr. montandoni and Notophthalmus. All the investigated species display: cholinergic innervation better developed than adrenergic, no qualitative differences regarding the fine structure of nerve fibers and terminals as compared to that previously described in the pancreas or in other glands, axo-axonal contacts. Their functional signification as peripheric synapses is suggested. Frequently neuro-glandular junctions with or without membrane specializations. The occurrence of the latter is discussed in connection with peripheral transmission of nervous impulse.