Mellon D, Lnenicka G
J Exp Biol. 1980 Feb;84:187-99. doi: 10.1242/jeb.84.1.187.
The morphologies and passive electrical parameters of fibres in two eye muscles of a surface- and a cave-dwelling crayfish were compared. In the cave-dwelling form the muscles contained fewer fibres, of less diameter, and hence had a smaller cross-sectional area. Current-voltage relationships were similar in both species. Input resistance was higher in the cave-dweller, but the difference was not as great as would be expected on the basis of geometry alone. Accordingly, the specific membrane resistance of muscle fibres in the cave-dweller is 50-60% smaller than that in the surface-dweller. This may account partially for the observation that identified excitatory junctional potentials in muscles of cave- and surface dwellers have similar amplitudes. We conclude that a functional oculomotor system is maintained in cave-dwelling crayfish, and that this system confers some positive selective advantage.
比较了生活在地表和洞穴中的小龙虾两只眼肌中纤维的形态和被动电学参数。在穴居形态中，肌肉含有的纤维更少，直径更小，因此横截面积也更小。两种小龙虾的电流-电压关系相似。穴居小龙虾的输入电阻更高，但差异并不像仅根据几何结构所预期的那么大。因此，穴居小龙虾肌肉纤维的比膜电阻比地表小龙虾小50% - 60%。这可能部分解释了以下观察结果：穴居和地表小龙虾肌肉中已识别的兴奋性突触后电位具有相似的幅度。我们得出结论，穴居小龙虾维持了一个功能性的动眼系统，并且这个系统赋予了一些积极的选择优势。
