Perforated patch

In whole-cell patch clamp mode the internal solution of the micropipette perfuses the cell replacing the much smaller cytosolic solution. Because of this, some soluble factors that modulate cellular excitability and infl uence signaling pathways are washed out via the micropipette causing altered intracellular signaling, cellular function, or the active state of ion channels. One of the commonly observed consequences is current run-down, which refers to the gradual loss of current over time. Key molecules have been added to the micropipette’s intracellular solution in order to impede current run-down. ATP and/or creatine/ phosphocreatine are added to prevent channel dephosphorylation and protease inhibitors are added to prevent proteolytic degradation of channel proteins [1]. However, these components are not always successful in preventing current run-down as other factors can elicit the slow demise of current recordings in whole-cell patch through the disruption of the actin cytoskeleton [2].