Giant excised patch recordings of recombinant ion channel currents expressed in mammalian cells

The giant excised patch variant of patch clamp recording combines microsecond time resolution of macroscopic currents with rapid exchange of the experimental solutions at the intracellular membrane surface. This technique has been applied to a limited number of cell types, including Xenopus oocytes, muscle cells, and photoreceptors. We have applied this technique to recording recombinant ion channel currents expressed in membrane patches excised from HEK293 cell lines. Giant inside-out patch recordings of Na(+) channels and SK(Ca) type calcium-activated potassium channels show high temporal resolution and excellent signal to noise characteristics. This technique will facilitate the study of recombinant ion channels expressed in mammalian cells.