SEM studies of comparative membrane remodeling by endocytosis in toad urinary bladders following withdrawal of ADH and MZ

This is the authors' abstract. We don't add key points for this paper.

Vasopressin (ADH) and mezerein (MZ) induce transmembrane water flow through water channels inserted into the apical plasma membrane. The water channels are then recycled into the cytosol during retrieval following withdrawal of vasopressin or mezerein. Previously, we demonstrated that membrane retrieval occurs within 5 min following withdrawal ofADH or MZ even after stimulation for 15 or 10 min respectively. The apical membranes appear to undergo remodeling prior to a complete membrane restoration. The loss in microstructure are restricted to the mucosal face of the apical membrane. However, little is known about the apical membrane recycling process during probnged periods of hormone stimulation. We currently report on surface membrane remodelling in toad urinary bladders following prolonged stimulation with ADH and subsequent retrieval following removal of hormone. Toads, Bufo marinus , were doubly pithed and the urinary bladders were removed and suspended as sacs with an imposed osmotic gradient (1/10 diluted Ringer's solution). Some tissues were retained in ADH 100 mU/ml for 60 min with no change in buffer and then fixed.