Ion selectivity of scorpion toxin-induced pores in cardiac myocytes.
The lytic activity of parabutoporin (PP) and opistoporin 1 (OP1) on mammalian and bacterial membranes have been described. We investigated pore-formation and ion selectivity in cardiac myocytes by measuring the whole cell leak current by means of the patch clamp technique. Pore formation was observed as the induction of leak currents. Ion selectivity of the pores was indicated by the shift of the reversal potential (E(rev)) upon substitution of intra- and extra-cellular ions. Results were compared with the effect of gramicidin A (gramA). PP and OP1 induced a fluctuating leak current and indicate non-selectivity of PP-induced pores. PP- and OP1-induced pores are between 1.38 and 1.78 nm in diameter.
Elgar
Dale
D
School of Physiology, Nutrition and Consumer Sciences, North-West University, Subject Group Physiology, Private Bag X6001, Potchefstroom 2520, South Africa. fmsde@puknet.puk.ac.za
Verdonck
Fons
F
Grobler
Anne
A
Fourie
Carla
C
du Plessis
Johan
J
D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000633:toxicity*; D002413:Cations, Divalent / Q000378:metabolism; D002414:Cations, Monovalent / Q000378:metabolism; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism*; D002478:Cells, Cultured; D006096:Gramicidin / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012604:Scorpion Venoms / Q000633:toxicity*; D012605:Scorpions / Q000502:physiology*
D023181:Antimicrobial Cationic Peptides; D002413:Cations, Divalent; D002414:Cations, Monovalent; D012604:Scorpion Venoms; C496148:parabutoporin, Parabuthus schlechteri; D006096:Gramicidin