W-7 inhibits voltage-dependent K(+) channels independent of calmodulin activity in rabbit coronary arterial smooth muscle cells.

Hongliang Li, Il-Whan Choi, Da Hye Hong, Youn Kyoung Son, Sung Hun Na, Won-Kyo Jung, Amy L Firth, In Duk Jung, Yeong-Min Park, Won Sun Park

European journal of pharmacology 2015 Mar 5

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We investigated the effect of W-7, a calmodulin inhibitor, on voltage-dependent K(+) (Kv) channels in freshly isolated coronary arterial smooth muscle cells using the whole-cell patch clamp technique. The amplitude of Kv currents was inhibited by W-7 in a concentration-dependent manner, with an IC50 value of 3.38±0.47μM and a Hill coefficient of 0.84±0.10. W-7 shifted the activation curve to a more positive potential but had no significant effect on the inactivation curve, which indicated that W-7 inhibited the Kv current in a closed state of the Kv channel. Another calmodulin inhibitor, W-13, had no significant effect on Kv currents and did not change the inhibitory effect of W-7 on Kv channels. From these results, we conclude that W-7 inhibited the Kv current in a dose-dependent manner, but this inhibition occurred independent of calmodulin activity and in a closed (inactivated) state of the Kv channels. Copyright © 2015 Elsevier B.V. All rights reserved.

Citation

Hongliang Li, Il-Whan Choi, Da Hye Hong, Youn Kyoung Son, Sung Hun Na, Won-Kyo Jung, Amy L Firth, In Duk Jung, Yeong-Min Park, Won Sun Park. W-7 inhibits voltage-dependent K(+) channels independent of calmodulin activity in rabbit coronary arterial smooth muscle cells. European journal of pharmacology. 2015 Mar 5;750:14-9