In vitro formation of neuromuscular junctions between adult Rana muscle fibres and embryonic Xenopus neurons.
In vitro formation of neuromuscular junctions between adult Rana muscle fibres and embryonic Xenopus neurons.
复制标题
成年林蛙肌纤维和胚胎爪蟾神经元之间神经肌肉连接的体外形成。
DOI：
10.1098/rspb.1987.0027
复制
发表时间：
1987
期刊：
影响因子：
--
通讯作者：
Miledi,R
中科院分区：
文献类型：
--
作者：
Nakajima,Y;Glavinović,MI;Miledi,R
青蛙的成体肌纤维与来自非洲爪蟾胚胎的神经元一起培养。培养物的电子显微镜和电生理学检查表明，异种特异性（爪蟾-蛙）神经肌肉接头在体外形成。神经突没有任何雪旺细胞覆盖，沿着肌纤维的任何地方都有接触，这些连接类似于神经肌肉突触原位早期再生过程中看到的连接。如果在神经元培养之前将肌纤维去神经支配，则通过自发微型终板电位或电流的存在推断出的功能性接触会更常见。微型端板电流（m.e.p.cs）的振幅分布不均匀，许多小事件在记录噪声中丢失，其平均振幅远小于m.e.p.cs。 e. p。 cs 位于原蚓状肌中。 m 的衰减时间常数。 e. p。异质特异性连接中的cs在体外形成的时间比m的衰变时间长几倍。 e. p。 cs在原来的肌肉里。对离子导入乙酰胆碱 (ACh) 引起的膜电流噪声的分析表明，m 的衰减速度较慢。 e. p。由于ACh打开的通道的寿命延长以及ACh受体的重复激活，体外形成的连接中的cs变得可能，这是由于连接中相对缺乏胆碱酯酶而成为可能的。
Adult muscle fibres of the frogRana temporariawere cultured with neurons from embryos of the frogXenopus laevis. Electron microscopical and electro-physiological examination of the cultures showed that hetero-specific (Xenopus- Rana) neuromuscular junctions were formedin vitro. Nerve processes, without any Schwann cell covering, made contacts anywhere along a muscle fibre, and the junctions resembled those seen during early regeneration of neuromuscular synapsesin situ. Functional contacts, as inferred by the presence of spontaneous miniature endplate potentials, or currents, were more common if the muscle fibres were denervated prior to culturing with neurons. Miniature endplate currents (m. e. p. cs) had a skewed amplitude distribution, with many small events lost in the recording noise, and their mean amplitude was much smaller than that of m. e. p. cs in the original lumbricalis muscle. The time constant of decay of m. e. p. cs in the hetero-specific junctions formed invitrowas several times longer than the decay of m. e. p. cs in the original muscle. Analysis of membrane current noise elicited by ionophoretically applied acetylcholine (ACh) suggests that the slower decay of m. e. p. cs in the junctions formedin vitrois due to a prolonged lifetime of the channels opened by ACh and to repetitive activation of ACh-receptors, which becomes possible because of a comparative lack of cholinesterase in the junctions.