Walz B
Cell Tissue Res. 1979 May 18;198(2):335-48. doi: 10.1007/BF00232015.
Microvillar (receptive) and external (non-receptive) portions of the plasmalemma of photoreceptor cells of Hirudo were compared electron microscopically in thin sections and freeze-fracture replicas. A morphometric approximation showed that the surface area of the microvillar membrane is about 19 times larger than that of the external membrane. The microvillar membrane most probably undergoes extensive membrane turnover. In both segments of the membrane the particles associated with the P- and the E-fracture faces are randomly distributed except at some specific sites. The particles adhere predominantly to the P-faces. The particle densities on the fracture faces of the microvillar membrane differ from those of the external membrane. The P-face particles of the external membrane appear to be larger than those of the microvillar membrane. It is suggested that the P-face particles of the microvillar membrane represent sites where the photopigment is incorporated into the membrane. The distinguishing structural features correspond to the functional differences postulated for both portions of the plasma membrane.
利用超薄切片和冷冻蚀刻复型技术，在电子显微镜下对水蛭光感受器细胞质膜的微绒毛（感受性）部分和外部（非感受性）部分进行了比较。形态测量学估算表明，微绒毛膜的表面积约为外部膜表面积的19倍。微绒毛膜很可能经历广泛的膜更新。在膜的两个部分中，与P面和E面相关的颗粒除了在某些特定部位外均呈随机分布。颗粒主要附着在P面上。微绒毛膜断裂面上的颗粒密度与外部膜不同。外部膜的P面颗粒似乎比微绒毛膜的P面颗粒大。有人认为，微绒毛膜的P面颗粒代表了光色素掺入膜的部位。这些独特的结构特征与质膜这两个部分所假定的功能差异相对应。
