Ca2+ and K+ current in cultured vascular smooth muscle cells from rat aorta.

Ca2+ (ICa) and K+ (IK) currents were recorded in single cultured cells from rat aorta using the whole cell clamp technique with patch electrodes. ICa was detected at -30 mV, and at 20 mV it reached a peak in about 10 ms and decayed with a t1/2 = 50 ms. The mean maximum slope conductance (GCa) was 30 microseconds/cm2. lK was detected at -10 mV and at 20 mV reached its maximum with a t1/2 = 12 ms. For IK, GK = 200 microseconds/cm2. These channels can be activated during action potentials and play a role in the excitation and contraction of vascular smooth muscle cells.