Interaction of acetylcholine with Kir6.1 channels heterologously expressed in human embryonic kidney cells

Abstract Kir6.1 subunit is one of the pore-forming components of K ATP channel complex. The endogenous modulation of Kir6.1 subunit function has been largely unknown. Whether acetylcholine modulated the function of Kir6.1 subunit stably expressed in human embryonic kidney (HEK-293) cells was examined in the present study using the whole-cell patch-clamp technique. Acetylcholine from 1–100 μM concentration-dependently stimulated the heteologously expressed and PNU-37883A sensitive Kir6.1 channels ( p ATP currents. Pretreatment of the transfected HEK-293 cells with atropine, α-bungarotoxin, mecamylamine, prazocine, propranolol, or dihydro-β-erythroidine hydrobromide did not alter the stimulatory effect of acetylcholine on Kir6.1 currents. When intracellular ATP was increased from 0.3 mM to 5 mM, acetylcholine at 10 μM still exhibited its stimulatory effect (−16.4 ± 2.3 to −25.5 ± 3.8 pA/pF, n  = 8, p