Herrera A A
J Physiol. 1984 Oct;355:267-80. doi: 10.1113/jphysiol.1984.sp015418.
The incidence of focal polyneuronal innervation was measured at end-plates in normal and reinnervated sartorius muscles from Rana pipiens either in the presence of curare to partially block neuromuscular transmission or in normal Ringer solution after pre-treatment with formamide to block excitation-contraction coupling. The incidence of polyneuronal innervation estimated with curare in normal muscles during the winter (19%) was significantly higher than the incidence in summer (9%). After formamide treatment, large end-plate potentials (e.p.p.s) and miniature e.p.p.s (m.e.p.p.s) could be recorded in Ringer solution containing physiological levels of Ca2+. For both normal and reinnervated muscles, higher levels of polyneuronal innervation could be recorded in normal Ringer solution after formamide treatment compared with levels measured in the presence of curare. This was true whether randomly selected end-plates or the same group of identified end-plates were examined before and after formamide treatment. Quantal content in normal Ringer solution containing 1.8 mM-Ca2+ was measured as the ratio of mean e.p.p. amplitude divided by mean m.e.p.p. amplitude. In randomly selected samples of normal end-plates the range of quantal contents seen was 18-112 (mean 50). For reinnervated end-plates 60 days after nerve crush, quantal contents were 6-181 (mean 54). It was concluded that formamide pre-treatment is a more sensitive technique for estimating the incidence of focal polyneuronal innervation and that, with appropriate controls, it can be used to measure quantal transmitter release accurately without using synaptic blocking agents.
在正常和重新神经支配的豹蛙缝匠肌终板处，测量局灶性多神经元支配的发生率。测量时，要么使用箭毒部分阻断神经肌肉传递，要么在经甲酰胺预处理以阻断兴奋 - 收缩偶联后，置于正常任氏液中。冬季正常肌肉中用箭毒估计的多神经元支配发生率（19%）显著高于夏季（9%）。甲酰胺处理后，在含有生理水平Ca2+的任氏液中可记录到大型终板电位（e.p.p.s）和微型终板电位（m.e.p.p.s）。对于正常和重新神经支配的肌肉，与在箭毒存在下测量的水平相比，甲酰胺处理后在正常任氏液中可记录到更高水平的多神经元支配。无论在甲酰胺处理前后检查的是随机选择的终板还是同一组已识别的终板，都是如此。含有1.8 mM - Ca2+的正常任氏液中的量子含量通过平均e.p.p.幅度除以平均m.e.p.p.幅度的比值来测量。在随机选择的正常终板样本中，观察到的量子含量范围为18 - 112（平均50）。对于神经挤压60天后的重新神经支配终板，量子含量为6 - 181（平均54）。得出的结论是，甲酰胺预处理是估计局灶性多神经元支配发生率的更敏感技术，并且在适当的对照下，它可用于在不使用突触阻断剂的情况下准确测量量子递质释放。
