Lang F, Cleveland M B, Atwood H L
J Neurobiol. 1979 Nov;10(6):609-14. doi: 10.1002/neu.480100608.
Neuromuscular transmission was measured in muscles of spider crabs (Hyas areneus) and lobsters (Homarus americanus). Solutions containing 40 and 10 mM/1 Mg++, which were approximately the same as those measured in the blood of Hyas and Homarus, respectively, were used to soak the preparations prior to testing. In Homarus, neuromuscular transmission was severely depressed by 40 mM Mg++. In spider crabs, neuromuscular transmission was not severely depressed. Although the amount of transmitter released by nerve impulses was reduced, total membrane depolarization during trains of impulses was not reduced because a compensating increase in muscle fiber membrane resistance occurred in Hyas preparations exposed to M Mg++. Hyas, but not Homarus, is physiologically adapted to function at relatively high blood Mg++ concentrations.
在蜘蛛蟹（Hyas areneus）和龙虾（美洲螯龙虾，Homarus americanus）的肌肉中测量了神经肌肉传递。分别使用含有40 mM/1和10 mM/1镁离子（Mg++）的溶液浸泡标本，这两种溶液的浓度大致与在Hyas和Homarus血液中测得的浓度相同，然后进行测试。在美洲螯龙虾中，40 mM Mg++会严重抑制神经肌肉传递。在蜘蛛蟹中，神经肌肉传递并未受到严重抑制。尽管神经冲动释放的递质数量减少，但在冲动串期间总的膜去极化并未减少，因为在暴露于镁离子的Hyas标本中，肌纤维膜电阻发生了补偿性增加。蜘蛛蟹而非美洲螯龙虾在生理上适应于在相对较高的血液镁离子浓度下发挥功能。
