The holding potential for voltage-clamp recordings was 70 mV, and responses were digitized at 10 kHz.
(D – F ) The same groups of cells are shown on correlation plots for meaningful (both biologically and statistically; see text) pairs of cell properties: threshold potentials for voltage-gated sodium and stable potassium currents (D ), membrane resistance and capacitance (E ), and ionic currents amplitudes (F ).
Membrane potentials in voltage clamp were corrected for the voltage drop across the uncompensated residual series resistance (Rs: 0.8 ± 0.1 MΩ, n = 10, after up to 80% compensation) and for a liquid junction potential (–4 mV).
In addition, the streaming potential mechanism for voltage difference generation is such that faster flow makes for larger voltage differences which is inconsistent with published observations that show an exactly opposite relationship [12], where it is clear that the highest voltages are recorded during the least transpirational activity (and therefore slowest flow) and vice versa.
Membrane resistance and action potential duration decreased only slightly in septic action potentials, suggesting a limited role, at best, for voltage gated K and Ca channels.
Analysis of the probability of VDAC to be open at varying potentials showed similar voltage gating for WT VDAC and S193E with characteristic bell-shaped plots.
These variables included activation potentials for sodium and slow potassium voltage-gated ionic currents; passive properties, such as membrane resistance and capacitance, and ionic current amplitudes.
We found that across all cells, the pair of properties that explained most of spike-output variance was a pair of activation potentials for sodium and stable potassium voltage-gated currents (INa and IKS; 18% of variance without interaction, 19% with interaction).
Couple this with line currents that are typically unbalanced and a potential for severe voltage unbalances can occur along with additional line power losses.
The latter effect was specific for voltages around the resting membrane potential (Fig. 5).
The major signal source for voltage-sensitive dyes is thought to be a postsynaptic potential rather than an action potential [21].
