Figure 5. No Kir current is detectable.

A, representative single cell, whole-cell patch-clamp recording of current elicited by protocol depicted in the inset in control bath solution. V_hold = −40 mV, V_test for 2.3 s duration to potentials ranging from −50 to −140 mV in 5 mV increments (for clarity currents for 10 mV increments are shown). Inward current is apparent for potentials negative to ∼60 mV. B, same protocol as A in response to 0.5 mm Ba²⁺. C, current–voltage plot for 2.3 s isochronal current in control solution; n = 6. D, 0.5 mm Ba²⁺-sensitive 2.3 s isochronal current–voltage relationship. Note the absence of detectable inward rectifier current.