Ultrastructure of the neuromuscular junction in the hindgut of Periplaneta americana and Locusta migratoria.
Ultrastructural characteristics of neuromuscular junctions were studied in the hindgut of periplaneta americana and Locusta migratoria. A great number of nerve bundles were found among the muscle fibers. Axon profiles, glial processes, and muscle cell processes made up the nerve bundles. Ultrastructurally rather different types of vesicles and granules were found in the axons and axon terminals. The number of agranular vesicle-containing terminals was usually low. Most frequently, small clear vesicles and moderately electrondense granules were found in the same terminals in different ratios. Nerve terminals containing electron-dense granules were also common in the muscle of proctodeum. Conventional synapses (with pre- and postsynaptic thickenings and accumulation of synaptic vesicles) were seen in the neuromuscular junctions of the proctodeum. The heterogeneous nature of nerve terminal structures on proctodeal muscle of cockroaches and locusts indicated that different active molecules may be stored in th different vesicles and granules.
D000818:Animals; D003058:Cockroaches / Q000033:anatomy & histology*; D004064:Digestive System / Q000294:innervation*; D006110:Grasshoppers / Q000033:anatomy & histology*; D008854:Microscopy, Electron; D009130:Muscle, Smooth / Q000294:innervation; D009469:Neuromuscular Junction / Q000648:ultrastructure*; D013045:Species Specificity