title: Portuguese Man-of-war (Physalia physalis) venom induces calcium influx into cells by permeabilizing plasma membranes.
abstract: Portuguese Man-of-war (Physalia physalis) nematocyst venom dose-dependently stimulates calcium (45Ca(2+)) influx into L-929, GH(4)C(1), FRL, and embryonic chick heart cells. Venom-induced calcium influx is not blocked by ouabain, vanadate, nor organic calcium channel blockers, but is blocked by transition metal cations, such as lanthanum and zinc. Venom-induced calcium influx is accompanied in a dose-dependent manner by the release of intracellular lactate dehydrogenase, indicating a loss in plasma membrane integrity and cytolysis. Concentrations of zinc that block 45Ca(2+) influx also block lactate dehydrogenase release. Lanthanum, which also blocks 45Ca(2+) uptake, does not neutralize the cytolytic activity of the venom, but rather inhibits the venom's cytolytic action at the level of the target cell plasma membrane. Our findings indicate that Man-of-war venom causes an influx of calcium into several different cells types, not just those of the cardiovascular system, and this influx likely occurs by permeabilizing the plasma membranes of cells.
authors.affiliation: Department of Physiology and Pharmacology,School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA.
authors.forename: L
authors.initials: L
authors.lastname: Edwards
authors.forename: D A
authors.initials: DA
authors.lastname: Hessinger
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002132:Calcium Radioisotopes; D002316:Cardiotonic Agents / Q000494:pharmacology; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002463:Cell Membrane Permeability / Q000187:drug effects*; D002642:Chick Embryo; D003064:Cnidarian Venoms / Q000494:pharmacology*; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D037402:Hydrozoa; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008168:Lung / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D008670:Metals / Q000494:pharmacology; D009206:Myocardium / Q000166:cytology / Q000378:metabolism; D010042:Ouabain / Q000494:pharmacology; D051381:Rats; D014638:Vanadates / Q000494:pharmacology
chemical_list: D002132:Calcium Radioisotopes; D002316:Cardiotonic Agents; D003064:Cnidarian Venoms; D008670:Metals; D014638:Vanadates; D010042:Ouabain; D007770:L-Lactate Dehydrogenase; D002118:Calcium