Voltage-Gated Potassium Channel In Brain Mitochondria

Transient cerebral ischemia is known to induce endogenous adaptive mechanisms such as the activation of mitochondrial ATP regulated potassium channels or Ca2+ regulated large conductance potassium channels that can prevent or delay neuronal injury. In this study a single channel activity was measured after patch-clamp of the mitoplasts isolated from gerbil hippocampus. In 70% of the all patches, a potassium selective current was recorded with mean conductance 109 ± 6 pS in symmetrical 150 mM KCl solution. The patch-clamp single channel studies showed properties of the voltage-gated potassium channel (Kv channel). We found that ATP/Mg2+ complex and Ca2+ ions had no effects on observed activity of ion channel. Observed channel was blocked by negative voltage and margatoxin (MgTx) a specific Kv1.3 channel inhibitor. The inhibition by MgTx was irreversible. We conclude that gerbil hippocampus mitochondria contain voltage-gated potassium channel (mitoKv) with properties similar to the surface membrane Kv1.3 channel which can play a role in control function of mitochondria as well as in ischemia-reperfusion phenomenon. This study was supported by grant No. P-N/031/2006 and Polish Mitochondrial Network MitoNet.pl.