Activation of latent K+ uniport in mitochondria treated with the ionophore A23187.
Addition of A23187 plus EDTA to energized mitochondria in KCl medium determines a rapid osmotic swelling due to K+ uptake. The swelling is fully reversed by uncoupler, is stimulated by quinine, and is accompanied by membrane depolarization and increased rate of respiration. A23187-treated mitochondria passively swell in K+ thiocyanate at neutral pH, under conditions where the H+-K+ antiporter appears to be silent. These data indicate that A23187 activates electrophoretic K+ flux, supporting the notion that Mg2+ depletion unmasks several ionic conductance pathways whose concerted interplay could provide a sensitive regulation of mitochondrial volume homeostasis.
Bernardi
P
P
Centro Nazionale delle Ricerche Unit for the Study of Physiology of Mitochondria, Padova, Italy.
Angrilli
A
A
Ambrosin
V
V
Azzone
G F
GF
D000001:Calcimycin / Q000494:pharmacology*; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone / Q000494:pharmacology; D007425:Intracellular Membranes / Q000187:drug effects / Q000502:physiology; D007700:Kinetics; D008564:Membrane Potentials / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D008933:Mitochondrial Swelling / Q000187:drug effects; D011188:Potassium / Q000378:metabolism* / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology; D011803:Quinine / Q000494:pharmacology; D013861:Thiocyanates / Q000494:pharmacology; D014634:Valinomycin / Q000494:pharmacology
D013861:Thiocyanates; D014634:Valinomycin; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone; D000001:Calcimycin; D011189:Potassium Chloride; D011803:Quinine; D011188:Potassium; C009941:potassium thiocyanate