Brink P R, Dewey M M
J Gen Physiol. 1978 Jul;72(1):67-86. doi: 10.1085/jgp.72.1.67.
The permeability of the septa of the earthworm in the median axon has been calculated for the anions fluorescein and its halogen derivatives. The values ranged from 5.4 X 10(-5) to 4 X 10(-6) cm/s. Previously, the septa had been shown to contain nexuses. By using freeze-fracture material, the surface area of nexus on the septal membranes was determined to be 4.5%, very similar to the percentage of nexus in the intercalated disk of mammalian myocardium. Plasma membrane permeability to these dyes was also calculated and shown to be much less than that of the septal membranes. In addition, an estimate of cytoplasmic binding for each dye was made, and most dyes showed little or no binding with the exception of aminofluorescein.
已计算出蚯蚓正中轴突隔膜对阴离子荧光素及其卤素衍生物的通透性。其数值范围为5.4×10⁻⁵至4×10⁻⁶厘米/秒。此前已证明隔膜含有连接子。通过使用冷冻断裂材料，确定隔膜膜上连接子的表面积为4.5%，这与哺乳动物心肌闰盘中连接子的百分比非常相似。还计算了质膜对这些染料的通透性，结果表明其远低于隔膜膜的通透性。此外，还对每种染料的细胞质结合情况进行了估计，除氨基荧光素外，大多数染料几乎没有或没有结合。
