Studies of nerve-muscle interactions in Xenopus cell culture: fine structure of early functional contacts

摘要: We have studied the fine structure of nerve-muscle contacts during first few hours synaptogenesis in embryonic Xenopus cell cultures. The precise timing contact was achieved by manipulating isolated spherical myocytes (myoballs) into with growth cones or neurites co-cultured spinal neurons. were shown to be functional whole-cell voltage-clamp recording nerve-evoked synaptic currents muscle cell. ultrastructure these examined thin-section electron microscopy. In total, 20 pairs periods ranging from min 12 hr, which time a substantial increase amplitude occurred. noncontacting cells and formed between natural encounters 1-d-old cultures also order identify features course morphological differentiation early contacts. Prominent area included: close apposition nerve membranes, greater frequency coated pits vesicles, thickening postsynaptic membrane. Occasionally, clusters clear vesicles occurred near presynaptic membrane, but no further sign active zone observed. comparison, definitive structure, well-formed extracellular basal lamina, widened cleft seen less than 24 hr old. This study identified may help us understand structural basis for interaction significance various specializations.