Description
Nigericin is a H+/K+ antiporter, which allows the electroneutral transport of these two ions in opposite directions across the mitochondrial inner membrane following the K+ concentration gradient. In the presence of K+, nigericin decreases pH in the mitchondrial matrix, thus, almost fully collapses the transmembrane ฮpH, which leads to the compensatory increase of the electric mt-membrane potential. Therefore, it is ideal to use to dissect the two components of the protonmotive force, ฮpH and mt-membrane potential. It is recommended to use the lowest possible concentration of nigericin, which creates a maximal mitochondrial hyperpolarization. In the study of Komlodi 2018 J Bioenerg Biomembr, 20 nM was applied on brain mitochondria isolated from guinea-pigs using 5 mM succinate in the LEAK state which caused maximum hyperpolarisation, but did not fully dissipate the transmembrane ฮpH. Other groups (Selivanov et al ; Lambert et al ), however, used 100 nM nigericin, which in their hands fully collapsed transmembrane ฮpH using succinate as a respiratory substrate on isolated rat brain and skeletal muscle in the LEAK state.
Reference: Dalmonte_2009_J_Biol_Chem Komlodi 2018 J Bioenerg Biomembr [1] [2]
MitoPedia concepts: Respiratory state
MitoPedia methods:
Respirometry,
Fluorometry