Cell-attached patch recordings from HeLa cells expressing TASK1, TASK3 and TASK1/3 heteromer, and from glomus cells isolated from ~2 week-old rat and mouse are shown. Pipette potential is held at +100 mV. Pipette solution contains (mM): 140 KCl, 5 EGTA, and 10 HEPES (pH 7.3) and the bath perfusion solution contains (mM): 140 KCl, 5 EGTA, 1 MgCl2 and 10 HEPES (pH 7.3). The single-channel conductance of TASK-like channel in glomus cells from both rat and mouse is most close to that of TASK1/3. Channel openings with conductance levels that are similar to those of TASK1 and TASK3 homomers are also observed in glomus cells but at much lower frequencies.