= Whole-cell recording
<Whole-cell recording> establishes intracellular electrical access by rupturing the membrane under a sealed <patch pipette> while retaining the <gigaohm seal>. Under adequate <voltage clamp>, the measured <electric current> combines contributions from accessible <ion channels>, <membrane capacitance> and <seal leak current>. <Current clamp> instead follows <membrane potential> while supplying a chosen <electric current>. <Whole-cell recording> is useful for linking a <biological cell>'s total electrical response to its <ion channels>, but neither mode automatically controls distant <dendrites> or preserves the original <cytosol>.
In the 1981 methods demonstration, a bovine chromaffin <biological cell> was tested before and after patch rupture. Small <voltage clamp> steps produced a much larger capacitive transient after break-in. Integrating it gave $5\,\mathrm{pF}$ for a $13\,\mu\mathrm m$ cell; its decay indicated <patch-clamp series resistance> below $20\,\mathrm{M\Omega}$. Depolarizing commands then revealed ionic <electric currents>. Separate <current clamp> recordings showed spontaneous <action potentials>. The comparison established access to the cell interior, rather than a claim that every pipette command equals <membrane potential>. Slower transients sometimes indicated incomplete rupture, and these small-cell results do not establish spatial control of a branched <neuron>.<Improved patch-clamp techniques for high-resolution current recording from cells and cell-free membrane patches by O. P. Hamill and others>[pp. 98–99, Figure 15 and following voltage-clamp and current-clamp discussion]{ref}
\Image[/whole-cell-access-resistance-and-clamp-response.png]
{title=Synthetic <whole-cell recording>: <patch-clamp series resistance> and passive responses}
{description=An original equivalent <electrical circuit> uses $R_s=20\,\mathrm{M\Omega}$, $R_m=200\,\mathrm{M\Omega}$ and $C_m=50\,\mathrm{pF}$. The <current clamp> step and <voltage clamp> step are separate synthetic experiments. The passive model omits active <ion channels>, <seal leak current>, pipette <capacitance> and amplifier dynamics. Curves are calculations, not experimental measurements.}
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