Activation of Ca(2+)-activated K+ channels by oxyphenamone in rabbit mesenteric vascular smooth muscle cells

Objective: To study the effects of oxyphenamone (Oxy) on activation of Ca(2+)-activated K+ channels in rabbit mesenteric vascular smooth muscle cells.

Methods: To measure the effect of Oxy on the Ca(2+)-activated K+ channel (BK (Ca) channel) activity in rabbit mesenteric vascular smooth muscle cells by using whole cell patch clamp techniques.

Results: Oxy reversibly increase BK (Ca) channel activity in rabbit mesenteric artery smooth muscle cells. Application of Oxy (0.1 mumol.L-1) to the perfusion solution caused significant increase in outward currents and its effect was completely abolished by washout; The outward currents K+ was inhibited by TEA (7.5 mmol.L-1); Oxy activated the BK (Ca) channel in a dose-dependent manner (0.01-10 mumol.L-1).

Conclusions: Oxy directly increase the activity of BK (Ca) channel activity in rabbit mesenteric vascular smooth muscle cells in dose-dependent manner.