Skaer H B, Maddrell S H, Harrison J B
Agricultural and Food Research Council Unit of Insect Neurophysiology & Pharmacology, Department of Zoology, Cambridge, UK.
J Cell Sci. 1987 Sep;88 ( Pt 2):251-65. doi: 10.1242/jcs.88.2.251.
This paper describes the structural characteristics and permeability properties of the smooth septate junctions between the upper Malpighian tubule cells of a blood-sucking bug, Rhodnius prolixus. The permeability of the paracellular route was tested only for solutes that could be demonstrated not to cross the epithelium via the cellular route. The intercellular clefts were readily permeated by sucrose, inulin and polyethylene glycol (PEG), showing a higher permeability to molecules of smaller radius (PEG versus sucrose). Negatively charged molecules permeated the clefts more readily than positively charged ones. The effects of pH, urea and luminal flow rate on permeability were studied. The results are discussed in relation to the physiological tightness of the Malpighian tubules to certain solutes and to its function as an excretory epithelium.
本文描述了吸血昆虫罗得西亚锥蝽（Rhodnius prolixus）上马尔皮基氏小管细胞间光滑的隔膜连接的结构特征和通透性特性。仅对那些经证实不会通过细胞途径穿过上皮的溶质测试了细胞旁途径的通透性。蔗糖、菊粉和聚乙二醇（PEG）很容易透过细胞间裂隙，对半径较小的分子（PEG与蔗糖相比）显示出更高的通透性。带负电荷的分子比带正电荷的分子更容易透过裂隙。研究了pH、尿素和管腔流速对通透性的影响。结合马尔皮基氏小管对某些溶质的生理紧密性及其作为排泄上皮的功能对结果进行了讨论。
