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XB-ART-17668
Pflugers Arch 1996 Oct 01;4326:1094-6. doi: 10.1007/s004240050240.
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Inhibition of IKs in guinea pig cardiac myocytes and guinea pig IsK channels by the chromanol 293B.

Busch AE , Suessbrich H , Waldegger S , Sailer E , Greger R , Lang H , Lang F , Gibson KJ , Maylie JG .


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The chromanol derivative 293B was previously shown to inhibit a cAMP regulated K+ conductance in rat colon crypts. Subsequent studies on cloned K+ channels from the rat demonstrated that 293B blocks specifically IsK channels expressed in Xenopus oocytes, but does not affect the delayed and inward rectifier Kv1.1 and Kir2.1, respectively. In the present study, the specificity of 293B for the cardiac K+ conductances IKs and IKr, and for the cloned guinea pig IsK channel and the human HERG channel, which underly IKs and IKr, respectively, was analyzed. 293B inhibited both the slowly activating K+ conductance IKs in cardiac myocytes and guinea pig IsK channels expressed in Xenopus oocytes with a similar IC50 (2-6 micromol/l). In contrast, high concentrations of 293B had only a negligible effect on the more rapid activating IKr. Similarly, 293B exerted no effect on HERG channels expressed in Xenopus oocytes. In summary, 293B appears to be a rather specific inhibitor of IKs and the underlying IsK channels.

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Species referenced: Xenopus laevis
Genes referenced: camp kcne1 kcnh2

References [+] :
Busch, The novel class III antiarrhythmics NE-10064 and NE-10133 inhibit IsK channels expressed in Xenopus oocytes and IKs in guinea pig cardiac myocytes. 1994, Pubmed, Xenbase