Inhibition of HERG channels stably expressed in a mammalian cell line by the antianginal agent perhexiline maleate

Walker, Bruce D.; Valenzuela, Stella M.; Singleton, C.; Tie, H.; Bursill, Jane A.; Wyse, Kenneth R.; Qiu, Min; Breit, Samuel N.; Campbell, Terence J.

doi:10.1038/sj.bjp.0702502

Cited by 58 publications

(31 citation statements)

References 35 publications

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“…Sites in the outer pore region such as G628, G631, S620, A614, and V630 have been known to involve HERG channel inactivation, which also postulated as a binding site(s) of the drug acting with the inactivated HERG channel [33] . H587 of the S5-P loop [34] and M651 of the S6 sites [35] also involved HERG inactivation kinetics.…”

Section: Discussionmentioning

confidence: 99%

Inhibitory effects of coronary vasodilator papaverine on heterologously-expressed HERG currents in Xenopus oocytes

Kim

Lee

Son

et al. 2007

Acta Pharmacologica Sinica

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Aim: To characterize the effects of papaverine on HERG channels expressed in Xenopus oocytes as well as cardiac action potential in rabbit ventricular myocytes. Methods: Conventional microelectrodes were used to record action potential in rabbit ventricular myocytes. HERG currents were recorded by 2-electrode voltage clamp technique in Xenopus oocytes injected with HERG cRNA. Results: Papaverine increased the cardiac action potential duration in rabbit ventricular myocytes. It blocked heterologously-expressed HERG currents in a concentration-dependent manner (IC 50 71.03±4.75 µmol/L, NH 0.80, n=6), whereas another phosphodiesterase inhibitor, theophylline (500 µmol/L), did not. The blockade of papaverine on HERG currents was not voltage-dependent. The slope conductance measured as a slope of the fully activated HERG current-voltage curves decreased from 78.03±4.25 µS of the control to 56.84±5.33, 36.06±6.53, and 27.09±5.50 µS (n=4) by 30, 100, and 300 µmol/L of papaverine, respectively. Papaverine (100 µmol/L) caused a 9 mV hyperpolarizing shift in the voltage-dependence of steady-state inactivation, but there were no changes in the voltage-dependence of HERG current activation. Papaverine blocked HERG channels in the closed, open, and inactivated states. Conclusion: These results showed that papaverine blocked HERG channels in a voltage-and state-independent manner, which may most likely be the major mechanism of papaverine-induced cardiac arrhythmia reported in humans.

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Section: Discussionmentioning

confidence: 99%

Inhibitory effects of coronary vasodilator papaverine on heterologously-expressed HERG currents in Xenopus oocytes

Kim

Lee

Son

et al. 2007

Acta Pharmacologica Sinica

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“…Examples of commonly used background cell lines include HEK 293, CHO-K1, and L-929. [16][17][18] The most accurate and reliable procedure for measuring inhibition of hERG currents is voltage clamp using the whole-cell configuration of the patch clamp technique, but this suffers from the limitation of low throughput due to the labor-intensive nature of the work.…”

Section: Introductionmentioning

confidence: 99%

Characterization of a hERG Screen Using the IonWorks HT: Comparison to a hERG Rubidium Efflux Screen

Sorota¹,

Zhang²,

Margulis³

et al. 2005

ASSAY and Drug Development Technologies

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The introduction of parallel patch clamp instruments offers the promise of moderate-throughput, high-fidelity voltage clamp for drug screening assays. One such device, the IonWorks HT (Molecular Devices, Sunnyvale, CA), was evaluated and compared to conventional human ethera- go-go-related gene (hERG) patch clamp data and an alternative functional screen based on rubidium flux. Data generated by the IonWorks HT and rubidium assays were compared to determine if either offered superior predictive value compared to conventional patch clamp. Concentration-effect curves for a panel of known hERG blockers were shifted to higher concentrations on the IonWorks HT compared to conventional voltage clamp determinations. The magnitude of the potency shifts was compound-specific and ranged from no shift (e.g., quinidine) to over 200-fold (astemizole). When the extreme value for astemizole was disregarded, the potency shift for 13 other known reference standards was 12-fold or less, with an average shift of fivefold. The same subset of compounds in the rubidium efflux assay exhibited an average potency shift of 12-fold. To provide a simulation of how the IonWorks HT assay might perform in a single concentration screening mode, a panel of test compounds was evaluated. The IonWorks HT screen did not outperform the rubidium efflux screen in predicting conventional voltage clamp measurements. The most likely explanation appears to rest with variable and compound-specific potency shifts in the IonWorks HT assay. The variable potency shifts make it difficult to select a screening concentration that meets the criterion of a high positive predictive value while avoiding false-positives.

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“…We next investigated the affinity of four drugs established previously to block hERG in the high nanomolar or micromolar range-quinidine (Lees-Miller et al, 2000), perhexiline (Walker et al, 1999a), erythromycin (Volberg et al, 2002), and dl-sotalol (Kirsch et al, 2004)-for N588E-hERG, WT-hERG, and N588K-hERG constructs expressed in CHO cells. Typical examples of current traces recorded from WT-, N588K-, and N588E-hERG in the presence and absence of 3 M quinidine are illustrated in Fig.…”

Section: State Dependence Of Drug Binding To Herg 1445mentioning

confidence: 99%

Drug Binding to the Inactivated State Is Necessary but Not Sufficient for High-Affinity Binding to Human Ether-à-go-go-Related Gene Channels

Perrin

Kuchel²,

Campbell³

et al. 2008

Mol Pharmacol

123

168

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Drug block of the human ether-à -go-go-related gene Kϩ channel (hERG) is the most common cause of acquired long QT syndrome, a disorder of cardiac repolarization that may result in ventricular tachycardia and sudden cardiac death. We investigated the open versus inactivated state dependence of drug block by using hERG mutants N588K and N588E, which shift the voltage dependence of inactivation compared with wildtype but in which the mutated residue is remote from the drug-binding pocket in the channel pore. Four high-affinity drugs (cisapride, dofetilide, terfenadine, and astemizole) demonstrated lower affinity for the inactivation-deficient N588K mutant hERG channel compared with N588E and wild-type hERG. Three of four low-affinity drugs (erythromycin, perhexiline, and quinidine) demonstrated no preference for N588E over N588K channels, whereas dl-sotalol was an example of a low-affinity state-dependent blocker. All five state-dependent blockers showed an even lower affinity for S620T mutant hERG (no inactivation) compared with N588K mutant hERG (greatly reduced inactivation). Computer modeling indicates that the reduced affinity for S620T compared with N588K and wild-type channels can be explained by the relative kinetics of drug block and unblock compared with the kinetics of inactivation and recovery from inactivation. We were also able to calculate, for the first time, the relative affinities for the inactivated versus the open state, which for the drugs tested here ranged from 4-to 70-fold. Our results show that preferential binding to the inactivated state is necessary but not sufficient for high-affinity binding to hERG channels.

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Inhibition of HERG channels stably expressed in a mammalian cell line by the antianginal agent perhexiline maleate

Cited by 58 publications

References 35 publications

Inhibitory effects of coronary vasodilator papaverine on heterologously-expressed HERG currents in Xenopus oocytes

Inhibitory effects of coronary vasodilator papaverine on heterologously-expressed HERG currents in Xenopus oocytes

Characterization of a hERG Screen Using the IonWorks HT: Comparison to a hERG Rubidium Efflux Screen

Drug Binding to the Inactivated State Is Necessary but Not Sufficient for High-Affinity Binding to Human Ether-à-go-go-Related Gene Channels

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