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Bioblasts - Richard Altmann and MiPArt by Odra Noel
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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 ΔpH, 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, ΔpH 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 ΔpH. Selivanov and his co-workers [1] and Lambert [2], however, used 100 nM nigericin, which in their hands fully collapsed transmembrane ΔpH 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

MitoPedia concepts: Respiratory state 

MitoPedia methods: Respirometry, Fluorometry