ELEVATION IN PRESYNAPTIC CA2+ LEVEL ACCOMPANYING INITIAL NERVE MUSCLE CONTACT IN TISSUE-CULTURE

被引:52
作者
DAI, ZS
PENG, HB
机构
[1] Department of Cell Biology and Anatomy, Curriculum in Neurobiology University of North Carolina, Chapel Hill
关键词
D O I
10.1016/0896-6273(93)90199-2
中图分类号
Q189 [神经科学];
学科分类号
071006 ;
摘要
Nerve-muscle cocultures were used to study the relationship between neuronal Ca2+ level and the earliest nerve-muscle interaction. Xenopus spinal cord neurons were loaded with Ca2+ indicators and monitored by digital video microscopy as a myoball was manipulated into contact with it. Transmitter release was measured from the myoball by whole-cell recording. We observed a 1.5- to 6-fold increase in Ca2+ level in the neurite upon contact with a myoball. Fifty percent of the pairs showing Ca2+ elevation were also positive for neurotransmission. This Ca2+ rise was suppressed by lifting away the myoball, by Ca2+-free solution, or by suramin, a polyanionic compound that interferes with cell surface receptors. This suppression was accompanied by a reduction in transmitter release. The specificity of the nerve-muscle contact-induced Ca2+ rise was shown by its absence upon neuron-neuron contact. Naturally formed nerve-muscle contacts also showed an elevation in presynaptic Ca2+ level. Thus, this elevation appears to be a physiological step in the early stage of synaptogenesis and is likely mediated by muscle-derived molecules.
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页码:827 / 837
页数:11
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