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. Author manuscript; available in PMC: 2007 Sep 7.
Published in final edited form as: J Membr Biol. 2007 Mar 8;213(1):19–29. doi: 10.1007/s00232-006-0037-y

Figure 5.

Figure 5

Single channel analysis of KIR channels. (A) Single unitary events recorded in the cell-attached configuration from a HAPSM cell and HEK293 cells expressing either Kir2.1 or Kir2.4. Currents, filtered at 500 Hz, were recorded at various test potentials from −120 to +60 mV in symmetrical 140/140 mM K+, with the closed state indicated. Due to the low frequency of closings with Kir2.4 channels, recordings were also made in the presence of 300 μM BaCl2 in the patch pipette. (B) All points amplitude histograms for recordings shown in (A) at a test potential of −80 mV for identical 20 s recordings (0.1 pA bin-width). (C) Mean single channel I-V relationships recorded in HPASM cells (closed squares, n=6) and HEK293 cells expressing either Kir2.1 (open circles n=7) or Kir2.4 (open triangles, n=4) with the inset showing recordings in the presence BaCl2 (n=5). Slope conductances were obtained by linear regression giving values of 20.5 ± 0.9 pS, 19.6 ± 0.9 pS, 19.4 ± 1.7 pS, 22.0 ± 0.9 pS, for HPASM, Kir2.1, Kir2.4, and Kir2.4 in the presence of Ba2+, respectively.