title: Annexins from Ehrlich ascites cells inhibit the calcium-activated chloride current in Xenopus laevis oocytes.
abstract: The effect of annexins II, III and V, purified from different species, on the calcium-activated chloride current across the stage-V to stage-VI Xenopus laevis oocyte membrane was tested either directly, using calcium entry mediated by depolarization, by A23187 permeabilization of oocytes or indirectly by quisqualate stimulation of a metabotropic glutamate receptor in the membrane expressed by the oocyte after injection of mRNA. The annexins isolated from the Ehrlich ascites cell, which is a mouse tumor cell, were found to be potent inhibitors of the chloride current, showing half-maximal inhibition at 50 nM, whereas no block was found using bovine or porcine annexins isolated from lung tissue. Of the annexins tested, we found annexin III to be naturally occurring in the oocyte, while only trace amounts of annexins II and V could be demonstrated. The inhibition pattern varied somewhat according to the stimulus method, the inhibition being more complete when an indirect stimulus via the metabotropic receptor was applied compared to a direct calcium stimulus.
authors.affiliation: The August Krogh Institute, University of Copenhagen, Universitetsparken 13, DK-2100 Copenhagen, Denmark.
authors.forename: A J
authors.initials: AJ
authors.lastname: Jorgensen
authors.forename: P
authors.initials: P
authors.lastname: Bennekou
authors.forename: K
authors.initials: K
authors.lastname: Eskesen
authors.forename: B I
authors.initials: BI
authors.lastname: Kristensen
mesh_terms: D000818:Animals; D017306:Annexin A2 / Q000302:isolation & purification / Q000494:pharmacology; D017318:Annexin A3 / Q000302:isolation & purification / Q000494:pharmacology; D017304:Annexin A5 / Q000302:isolation & purification / Q000494:pharmacology; D017302:Annexins / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology*; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology; D002286:Carcinoma, Ehrlich Tumor / Q000737:chemistry; D002417:Cattle; D018118:Chloride Channels / Q000037:antagonists & inhibitors*; D005260:Female; D066298:In Vitro Techniques; D007476:Ionophores / Q000494:pharmacology; D008168:Lung / Q000737:chemistry; D008564:Membrane Potentials; D051379:Mice; D009865:Oocytes / Q000187:drug effects* / Q000378:metabolism*; D013045:Species Specificity; D013552:Swine; D014982:Xenopus laevis
chemical_list: D017306:Annexin A2; D017304:Annexin A5; D017302:Annexins; D018118:Chloride Channels; D007476:Ionophores; D000001:Calcimycin; D017318:Annexin A3; D002118:Calcium