Key Points
- To determine the pharmacological sensitivity of ATP-sensitive K+ (KATP) currents to channel openers and the blockers glibenclamide, tolbutamide, and tetraethylammonium in arterial smooth muscle cells.
- Applied the whole-cell patch-clamp technique to single smooth muscle cells isolated from rabbit mesenteric artery.
- Evaluated current activation by synthetic openers (pinacidil, cromakalim, diazoxide) alongside current inhibition by elevated intracellular ATP and external blockers (glibenclamide, tolbutamide, TEA+).
- Synthetic openers pinacidil, cromakalim, and diazoxide activated K+-selective currents with half-activation values of 0.6 µM, 1.9 µM, and 37.1 µM, respectively, which were suppressed by elevating intracellular ATP.
- Glibenclamide inhibited KATP currents with a half-inhibition concentration of 101 nM, exhibiting markedly higher potency than tolbutamide (half-inhibition at 351 µM) and external TEA+ (half-inhibition at 6.2 mM).
Structured PICO
PPopulationSingle smooth muscle cells from rabbit mesenteric artery
IInterventionGlibenclamide, tolbutamide, and tetraethylammonium (TEA+)
OOutcomeInhibition of KATP currents measured by whole cell patch-clamp techniquesurrogate
Glibenclamide is a highly effective inhibitor of KATP channels in arterial smooth muscle compared to tolbutamide and TEA+, supporting its use in functional studies of vasorelaxation.