title: Vasopressin depolymerizes F-actin in toad bladder epithelial cells.
abstract: Vasopressin (AVP) induces the rapid fusion of water channel-containing vesicles with the luminal membrane of its target cell. We have carried out a quantitative study of the F-actin content of toad bladder epithelial cells, using the rhodamine phalloidin binding assay. As early as 1 min after AVP stimulation, there is a significant 15% reduction of cellular F-actin, which remains reduced by 20-30% for the duration of action of AVP. Comparable reductions were seen following 8-bromoadenosine 3',5'-cyclic monophosphate, 1-desamino-8-D-arginine vasopressin, and forskolin. F-actin content rose to and then exceeded that of control bladders after AVP washout. Inhibition of prostaglandin synthesis enhanced both water flow and the decrease of F-actin. In the living cell, stabilization of F-actin with NBD-phallacidin selectively inhibited water flow. In view of the rapidity of the response, we conclude that AVP shifts the equilibrium between F-actin and G-actin monomers, and this depolymerization may be required for vesicle fusion.
authors.affiliation: Department of Medicine, Albert Einstein College of Medicine, Bronx, New York 10461.
authors.forename: G H
authors.initials: GH
authors.lastname: Ding
authors.forename: N
authors.initials: N
authors.lastname: Franki
authors.forename: J
authors.initials: J
authors.lastname: Condeelis
authors.forename: R M
authors.initials: RM
authors.lastname: Hays
mesh_terms: D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000199:Actins / Q000378:metabolism*; D000546:Amanitins / Q000494:pharmacology; D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology*; D002024:Bufo marinus; D003894:Deamino Arginine Vasopressin / Q000494:pharmacology*; D004848:Epithelium / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D005260:Female; D066298:In Vitro Techniques; D046911:Macromolecular Substances; D008854:Microscopy, Electron; D011892:Rana catesbeiana; D001743:Urinary Bladder / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D000199:Actins; D000546:Amanitins; D046911:Macromolecular Substances; D001127:Arginine Vasopressin; D015124:8-Bromo Cyclic Adenosine Monophosphate; C028877:7-nitrobenz-2-oxa-1,3-diazole-phallacidin; D003894:Deamino Arginine Vasopressin