Abstract
Two K+ channel populations were identified in depolarized cell-attached membrane patches of myocytes freshly dispersed from the circular smooth muscle of guinea-pig proximal colon. First, a large-conductance (150 pS) Ca2+-activated K+ channel which was non-inactivating and sensitive to blockade by tetraethylammonium (TEA, 0.5–5 mM); and second, a smaller conductance K+ channel which opened and closed within 100 ms, was insensitive to TEA (0.5–5 mM), but was blocked by 5 mM 4-aminopyridine (4-AP) or maintained depolarization, and which had a unitary conductance of 12–13 pS. The averaged time course of these smaller conductance K+ channels closely resembled the time course of the 4-AP-sensitive, Ca2+-insensitive transient outward K+ current recorded in the whole-cell recording mode.
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Vogalis, F., Lang, R.J. Identification of single transiently opening (“A-type”) K channels in guinea-pig colonic myocytes. Pflugers Arch. 429, 160–164 (1994). https://doi.org/10.1007/BF00374307
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DOI: https://doi.org/10.1007/BF00374307