Palytoxin effects through interaction with the Na,K-ATPase in Xenopus oocyte.
Palytoxin (PTX) is known to bind to Na,K-ATPase, to inhibit its activity, and to induce cation conductance, but the mechanism of these effects is still poorly understood. In Xenopus oocytes, PTX induced a large cation conductance, an effect that could be prevented or reversed by ouabain for oocytes expressing Xenopus Na,K-pumps but not with those expressing Bufo Na,K-pumps. In both cases patch-clamp experiments demonstrated a 7-8 pS channel in the presence of PTX. A large PTX-induced conductance could be observed with minimal Na,K-pump inhibition. From the single PTX-induced channel and macroscopic whole oocyte conductance, and the number of Na,K-pumps, we can conclude that PTX-induced conductance occurs through a direct interaction of PTX with a small number of Na,K-pumps.
Wang
X
X
Institute of Pharmacology and Toxicology, University de Lausanne, Switzerland.
Horisberger
J D
JD
D000178:Acrylamides / Q000378:metabolism / Q000494:pharmacology*; D000818:Animals; D002025:Bufonidae; D003064:Cnidarian Venoms / Q000201:enzymology / Q000494:pharmacology*; D004553:Electric Conductivity; D007700:Kinetics; D009865:Oocytes / Q000187:drug effects* / Q000201:enzymology*; D018408:Patch-Clamp Techniques; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors / Q000187:drug effects / Q000378:metabolism*; D014982:Xenopus laevis; D000095702:Polyether Toxins
D000178:Acrylamides; D003064:Cnidarian Venoms; D000254:Sodium-Potassium-Exchanging ATPase; C010272:palytoxin; D000095702:Polyether Toxins