Effects of WIN 55,212-2 on I(K) current in cultured trigeminal ganglion neurons of rat.

To investigate the effects of WIN 55,212-2 on I(K) in cultured rat trigeminal ganglion (TG) neurons, whole-cell patch clamp techniques were used to record the I(K) before and after WIN 55,212-2 perfusion at different concentrations. 30 micromol/L WIN 55,212-2 markedly (35.7% +/- 7.3%, P < 0.01, n = 8) inhibited I(K) currents, and the currents were partially recovered after washing. 30 micromol/L WIN 55,212-2 also induced a significant depolarizing shift in conductance-voltage parameters (control: V0.5 = 10.43 +/- 4.25 mV, k = 16.27 +/- 3.86; WIN 55,212-2: V0.5 = 24.71 +/- 3.91 mV, k =16.69 +/- 2.75; n = 8, P < 0.01 for V0.5). 0.01 micromol/L WIN 55,212-2 slightly (27.0% +/- 7. 9%, P < 0.05, n = 7) increased I(K) currents, but had no significant change in conductance voltage parameters (control: V0.5 =10.74 +/- 5.27 mV, k = 17.33 +/- 2.96; WIN 55,212-2: V0.5 = 11.06 +/- 2.05 mV, k = 19.69 +/- 6.60; n = 7, P > 0.05 for V0.5 and k). These results suggested that WIN 55,212-2 has dual action, which might be through different receptors.