Role of vesicular transport in ADH-stimulated aggregate delivery

The effect of vasopressin on the cytoskeleton of the epithelial cell

Vasopressin (AVP) promotes the fusion of vesicles containing water channels with the apical membrane of receptor cells in the amphibian bladder and mammalian kidney. Fusion is accompanied by depolymerization of the actin cytoskeleton. In this review, we present the evidence for actin depolymerization by AVP in the whole cell, and the application of confocal microscopy and immunogold electron microscopy in localizing depolymerization to the apical region of the receptor cell.

The dynamics of intramembranous particles in the degradative pathways of the phagocytosed erythrocyte

The present study was designed to reveal membrane events during an erythrophagocytosis by electron microscopy. The erythrocytes, which were extravasated into rats' mesenteric lymph node sinuses by short clamping of the portal-vein and phagocytosed by fixed macrophages, were analysed at 0.5, 1, 3, 4 and 6 hr after reopening of the vein by using freeze-fracture and thin-section techniques. The results were as follows: the intramembranous particles of the phagocytosed erythrocyte aggregated after injection of lysosomal enzymes into the phagosome. The digested cytoplasm accumulated in the space between the phagosomal and erythrocyte membranes and was removed from the phagosome by bleb formation or invagination. Subsequently, the erythrocyte membranes lost their intramembranous particles and fragmented. The phagosome lost its density and erythrocyte-structure and became a vacuole (phagosomal ghost), which fractured lamellarly.

Current understanding of the cellular biology and molecular structure of the antidiuretic hormone-stimulated water transport pathway

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