The cerebral ganglion and nerve tracts of Moniliformis dubius show intense, specific, green fluorescence that is also associated with the lateral and apical sensory bulbs. Radioenzymatic assays showed that high levels of dopamine were present but only small amounts of the catecholamines norepinephrine and epinephrine were identified. Incubations of the proboscis sac in dilute solutions of dopamine increased fluorescence while incubations in reserpine resulted in loss of fluorescence. Nonfluorogenic amine octopamine was also detected radioenzymatically. Neutral red vitally stained a number of cells in the cerebral ganglion and the nerve tracts extending from the ganglion. Electron microscopy showed that many neurons contained electron-dense vesicles. The close association of the fluorescing, amine-containing nerve tracts with the sensory bulbs suggests that they may play a functional role in sensory reception and transmission in M. dubius. This is the first report on the presence of biogenic amines in the Acanthocephala.

1. The protein nitrogen, carbohydrate and amino acid contents of the rat duodenum, jejunum, upper and lower ileum have been determined for up to 3 hr following the feeding of a glucose-containing test diet.2. The changes in distribution of Hymenolepis diminuta within the intestine and the changes in worm total nitrogen and carbohydrate have been followed over the same period following the same diet.3. The glucose and TCA-soluble carbohydrate contents of the uninfected gut were approximately double those of the parasitized animals.

The cerebral ganglion of Moniliformis moniliformis consists of an outer single layer of cell bodies and an inner core of neuropile occupied by cellular processes. Morphological characteristics of 5 types of cellular processes have been described. Most of the processes in the neuropile were of large size, although sites containing numerous small processes (neurites) were also observed. Small processes in the neuropile were the sites of synaptic interaction. The majority of presynaptic membranes were well defined by the presence of electron-dense material at the inner leaflet, while postsynaptic membranes appeared to lack marked postsynaptic density. Round or flattened lucent vesicles were concentrated around the presynaptic membranes. Electron-dense and dense-cored vesicles were usually separated from the clear vesicles and situated at some distance from synaptic sites.

The morphology of the cerebral ganglion of the Acanthocephalan Moniliformis moniliformis was studied in serial sections using electron microscopy. The organization of the cerebral ganglion was typical of other invertebrates with the cell bodies forming a rind, 1 cell thick, and their processes forming the central core of the neuropile. The ganglion was surrounded by a connective tissue capsule composed of collagen-like fibrils. Externally, the free surface of the cell bodies was covered by an electron-dense extracellular lamina. Seventy-six cells were identified in every ganglion examined and, on the basis of their cellular characteristics, they were divided into 5 distinct cell types, classified as type A, B, C, D and E cells. The characteristic morphological features of each cell type have been described, and the distribution of the different cell types in the cerebral ganglion was mapped.

No abstract