The giant channel of the inner mitochondrial membrane is inhibited by cyclosporin A.
In patch-clamp experiments on rat liver mitoplasts, cyclosporin A inhibited the activity of the recently described (Petronilli, V., Szabó, I., and Zoratti, M. (1989) FEBS Lett. 259, 137-143) 1.3-nanosiemens channel of the inner mitochondrial membrane at concentrations in the 10(-8)-10(-7) M range. The inhibitor acts when present on the matrix side of membrane. The Ca2(+)-dependent "permeability transition channel" of mitochondria is inhibited by cyclosporin A in the same concentration range. The results suggest therefore that the same pore is responsible for the permeabilization of the inner mitochondrial membrane and for the conduction of the high currents observed in electrophysiological experiments.
Szabó
I
I
Consiglio Nazionale delle Ricerche Centro Studi, Istituto di Patologia Generale, Padova, Italy.
Zoratti
M
M
D000818:Animals; D015220:Calcium Channels / Q000187:drug effects*; D002462:Cell Membrane / Q000187:drug effects; D003524:Cyclosporins / Q000494:pharmacology*; D008564:Membrane Potentials / Q000187:drug effects; D008930:Mitochondria, Liver / Q000187:drug effects*; D051381:Rats
D015220:Calcium Channels; D003524:Cyclosporins