Figure 6. Claudin-2-dependent conductance events measured by trans-tight junction patch clamp display cation- and size-selective properties similar to transepithelial paracellular conductance measured over large areas.
(A–E) Current-voltage (I-V) relationships for events detected by trans-tight junction patch clamp in MDCKI monolayers with transgenic claudin-2 expression (+Cldn-2) under the ionic conditions shown. Pipette and basolateral buffer composition are indicated in mM. (F) Vrev was determined under each of the ionic conditions shown (n=4 to 7 per condition). (G) Cation permeability determined from shifts in trans-tight junction patch clamp Vrev (green line) or traditional (black line) bi-ionic potential measurements.