Calcium modulation of mitochondrial inner membrane channel activity.
Protocols were defined that enable patch-clamp studies of the approximately 107 pS voltage dependent channel and a class of activity we refer to as MCC (multiconductance channel) which is characterized by multiple levels and transitions as high as 1 to 1.5 nS. If free calcium was kept at 10(-7) M or lower during mitochondrial isolation, no activity was observed at low voltage (+/- 60 mV). If free calcium levels were higher, MCC activity was observed in about 96% of the patches. The observation of approximately 107 pS channel was enhanced from 2% to 68% of patches by washing isolated mitoplasts (mitochondria stripped of outer membrane) with EGTA. Increasing matrix calcium from 10(-9) to 10(-5) M decreased the probability of opening for the MCC and approximately 107 pS activities.
Kinnally
K W
KW
Dept. Biol. Sci., S.U.N.Y. Albany 12222.
Zorov
D
D
Antonenko
Y
Y
Perini
S
S
D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D004533:Egtazic Acid / Q000494:pharmacology; D004553:Electric Conductivity; D006801:Humans; D007425:Intracellular Membranes / Q000502:physiology*; D007473:Ion Channels / Q000187:drug effects / Q000502:physiology*; D007700:Kinetics; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D008929:Mitochondria, Heart / Q000502:physiology*; D008930:Mitochondria, Liver / Q000502:physiology*; D013367:Submitochondrial Particles / Q000502:physiology*
D007473:Ion Channels; D004533:Egtazic Acid; D002118:Calcium