The effect of Portuguese Man-of-war (Physalia physalis) venom on calcium, sodium and potassium fluxes of cultured embryonic chick heart cells

Portuguese Man-of-war venom markedly increases calcium (Ca-45(2+)) influx i nto primary, cultured, embryonic chick heart cells. This action is dose-dep endent, but is unaffected by organic calcium blockers (diltiazem, verapamil , nifedipine, nimodipine and mibefradil). On the other hand, certain trival ent (La3+, Gd3+) and divalent (Zn2+, Ni2+, Cu2+, Mn2+) metals inhibit venom -induced calcium influx. Sodium (Na-22(+)) influx into chick heart cells is also significantly increased by Man-of-war venom. Flecainide does not bloc k venom-induced sodium influx. The efflux of the potassium analogue, Rb-86( +), from heart cells is also significantly increased by the venom. The veno m, however, has little or no effect on rubidium (Rb-86(+)) or 2-deoxy-D-[2- H-3] glucose influx. (C) 1999 Elsevier Science Ltd. All rights reserved.