Key points class="unordered" style="list-style-type:disc" id="tjp12744-list-0001">Interstitial cells of Cajal (ICC) from murine colonic muscles express genes encoding inwardly rectifying K+ channels. Transcripts of Kcnj2 (Kir2.1), Kcnj4 (Kir2.3), Kcnj14 (Kir2.4), Kcnj5 (Kir3.4), Kcnj8 (Kir 6.1) and Kcnj11 (Kir6.2) were found in colonic ICC.A conductance with properties consistent with Kir2 channels was observed in ICC but not in smooth muscle cells (SMC).Despite expression of gene transcripts, G‐protein gated K+ channel (Kir3) and KATP (Kir6) currents were not resolved in ICC. KATP is a conductance prominent in SMC.Kir2 antagonist caused depolarization of freshly dispersed ICC and colonic smooth muscles, suggesting that this conductance is active under resting conditions in colonic muscles.The conclusion of the present study is that ICC express the Ba2+‐sensitive, inwardly rectifying K+ conductance in colonic muscles. This conductance is most probably a result of heterotetramers of Kir2 gene products, with this regulating resting potentials and the excitability of colonic muscles.
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