Regulation of Single-Channel Conductance of Voltage-Dependent Anion Channel by Mercuric Chloride in a Planar Lipid Bilayer.

The existence of mercury in various forms, e.g., elemental, organic, and inorganic has been known for decades. In any of these forms, it is poisonous to metabolism. In this, an investigation about the effect of the inorganic form of mercury, i.e., mercuric chloride (HgCl) to the mitochondrial voltage-dependent anion channel (VDAC), has been done after isolation from the cardiac and brain tissues of Wistar rats. In vitro electrophysiology experiments were performed in Cardiolipin planar lipid bilayer membrane (BLM) to study the change in the conductance, selectivity, and gating charge of VDAC post HgCl treatment. A reduction in mean conductance of VDAC from 4.3 ± 0.18 to 1.66 ± 0.11 nS was observed. Further, the Gating charge calculated before (± 3.5) and after HgCl treatment (± 2.3) showed significant difference. Later, VDAC's behavior was studied at different concentrations of HgCl ranging from 0.1 μM to 1 mM. The Inhibitory concentration (IC) was calculated from the linear regression plot. The IC was found to be 488.1 μM. In the asymmetrical HgCl (5:1), a permeability ratio of cation to anion was found to be 4.2. It is interpreted that VDAC functioning is affected due to the application of 4 mM HgCl and a reduction in the conductance, gating charge, and permeability of VDAC was detected. The results provide clues to HgCl-induced toxicity mediated through VDAC in the Cardiolipin BLM.