Potassium Channel Modulators

Potassium channels are essential in both excitable and non-excitable cells for the control of membrane potential, regulation of cell volume, and the secretion of salt, neurotransmitters and hormones. They are integral membrane proteins that allow the selective, diffusional passage of potassium ions across biological membranes, and are capable of up to 10,000-fold selectiv­ity of potassium over sodium.
2TM Potassium Channel Structure
6TM Potassium Channel Structure

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SML1033 A-278637 ≥98% A-278637 is a selective opener of ATP-sensitive K (KATP) channels (EC50 = 102 nM) that blocks contraction of bladder smooth muscle in both in vivo and in vitro assays. A-278637 is 15-fold more selective than nifedipine for bladder compared other smooth muscle KATP channels, and displays reduced effects on mean arterial pressure compared to other channel openers.
05-23-2005 Neuropeptide Y, Human - CAS 90880-35-6 - Calbiochem A potent vasoconstrictor.  
120002 Adenylyl-imidodiphosphate, Tetralithium Salt - CAS 72957-42-7 - Calbiochem Adenylyl-imidodiphosphate, Tetralithium Salt, CAS 72957-42-7, is a non-hydrolyzable ATP analog. A competitive inhibitor of ATP-dependent enzymes. Block ATP-sensitive Ca2+-activated K+ channels., A non-hydrolyzable ATP analog that acts as a competitive inhibitor of ATP-dependent enzyme systems.  
178270 Apamin, Bee Venom - CAS 24345-16-2 - Calbiochem Polypeptide neurotoxin known to pass through the blood-brain barrier.  
219672 CFTR Inhibitor III, OXO-172 - Calbiochem The CFTR Inhibitor III, OXO-172 controls the biological activity of CFTR. This small molecule/inhibitor is primarily used for Biochemicals applications.  
309795 DIDS, Disodium Salt - CAS 53005-05-3 - Calbiochem Binds covalently and irreversibly to the outer surface of human erythrocyte membranes.  
309866 Diltiazem, Hydrochloride - CAS 33286-22-5 - Calbiochem Synthetic benzothiazepine that acts as an L-type Ca2+ channel antagonist.  
324470 E-4031 - CAS 113558-89-7 - Calbiochem A potent and selective inhibitor of the rapid type of inactivating inward-rectifying K+ current (IK, IR) (IC₅₀ = 10 nM).  
356310 Glyburide - CAS 10238-21-8 - Calbiochem A sulfonylurea that selectively blocks ATP-sensitive K+ channels.  
401002 Iberiotoxin, Buthus tamulus, Recombinant, E. coli - CAS 129203-60-7 - Calbiochem  
422689 Kir2.1 Inhibitor, ML133 - CAS 185669-79-8 - Calbiochem The Kir2.1 Inhibitor, ML133, also referenced under CAS 185669-79-8, controls the biological activity of Kir2.1. This small molecule/inhibitor is primarily used for Cancer applications.  
528105 Picrotoxin, Anamirta cocculin - CAS 124-87-8 - Calbiochem A potent antagonist of GABA receptors (IC₅₀ = 240 nM) at synapses in the central nervous system.  
676777 (±)-Verapamil, Hydrochloride - CAS 152-11-4 - Calbiochem A papaverine derivative that blocks Ca2+ channels (principally the L-type) in smooth and cardiac muscle cells.  
A5513 N-Acetylprocainamide hydrochloride ≥99% (HPLC), powder Class III antiarrhythmic. Increases the duration of the action potential by decreasing the delayed outward potassium current, slightly decreasing the calcium current, and slightly depressing the inward rectifier potassium current. This is the active metabolite of procainamide that does not induce systemic lupus erythematosus.
A2647 Adenosine 5′-(β,γ-imido)triphosphate lithium salt hydrate ≥93% (HPLC), powder A non-hydrolyzable ATP analog. AMP-PNP competitively inhibits ATP-dependent enzyme systems, such as glutamine synthetase. It inhibits a number of enzymes which require the hydrolysis of ATP such as DNA topoisomerase II, SV40 large T-antigen helicase and a number of kinases. Blocks ATP-sensitive calcium-dependent potassium channels.
A9219 Agitoxin-2 from scorpion venom recombinant, expressed in E. coli, ≥98% (SDS-PAGE), lyophilized powder Potent Shaker K+ channel blocker . Useful as a probe for Kv channels.
A78403 4-Aminopyridine 98%  
A1289 Apamin from bee venom, ≥95% (HPLC) The only polypeptide neurotoxin that is known to pass the blood-brain barrier. Blocks ATP-type Ca+2-activated K+ channels.
A9459 Apamin synthetic, ≥97% (HPLC) The only polypeptide neurotoxin that is known to pass the blood-brain barrier. Blocks ATP-type Ca+2-activated K+ channels.
A7606 Aprindine hydrochloride ≥98% (HPLC), solid Aprindine hydrochloride is a class Ib antiarrhythmic and hERG channel blocker. Aprindine shows structure similarities to lidocaine and procainamide and is effective in treatment of patients with ventricular premature depolarizations, ventricular tachycardia, and supraventricular arrhythmias. Aprindine inhibits the activation of bovine brain cyclic 3′:5′-nucleotide phosphodiesterase (EC 3.1.4.17) by calmodulin and inhibits calmodulin-stimulated Ca-ATPase (ATP phosphohydrolase EC 3.6.1.3) activity.
SML0353 Azimilide dihydrochloride ≥97% (HPLC) Azimilide is an investigational class III anti-arrhythmic drug that blocks fast and slow components of the delayed rectifier cardiac potassium channels. It inhibits KV7.1 and KV11.1 potassium channels. Azimilide′s block of K+ currents is relatively selective for IKr over IKs: It potently blocks the rapidly activating component of the delayed rectifier, IKr (IC50 0.4 mM), and inhibits IKs (IC50 3 mM) with nearly 10-fold less potency. At 10 mM, it does not block the inward rectifier K+ current. It blocks (10 mM) the L-type Ca2+ current (ICa) in a use-dependent manner.
B9554 BDS-I ≥95%, lyophilized powder Specifically blocks the rapidly inactivating Kv3.4 channel.
B6936 3-Benzidino-6-(4-chlorophenyl)pyridazine ≥98% (HPLC), solid 3-Benzidino-6-(4-chlorophenyl)pyridazine is an inhibitor of delayed rectifier and transient outward potassium currents. The IC50 values for the blocking action of BCP on IKDR and IKA was calculated as 7.13 μM and 0.55 μM, respectively in acutely isolated rat hippocampal pyramidal neurons by using whole-cell patch-clamp technique. The parent compound, minaprine (Cat. No. M3157), has selective affinity for M1 muscarinic receptors and possesses memory-enhancing properties and also acts as an antidepressant.
B2186 BL-1249 ≥98% (HPLC) BL-1249 is a putative activator of potassium TREK-1 channel.
SML0866 BMS-191011 ≥98% (HPLC) BMS-191011 is a potent opener of BKCa opener (large-conductance Ca2+-activated K channel). The compound BMS-191011 has neuroprotective properties in rodent models of stroke, and induces dialation of rat retinal arterioles.
BM0012 BMS-191095 hydrochloride ≥98% (HPLC) BMS-191095 is a potent and selective mitochondrial ATP-sensitive K1 channel (KATP) channel opener devoid of peripheral vasodilating activity. BMS-191095 improves postischemic recovery of function and reduced lactate dehydrogenase release in the isolated rat hearts.
SML1313 BMS 204352 ≥98% (HPLC) BMS 204352 is a potassium channel modulator. Originally developed as a potent opener of large-conductance, calcium-activated (Maxi-K, KCa1.1, BK) potassium channels, BMS 204352 also acts as a positive modulator at Kv7 (KCNQ) channels.
B0753 2,3-Butanedione monoxime ≥98% DRK1 is a delayed rectifier (Kv2.1) cloned K+ channel from rat brain with consensus sites for protein kinase-dependent phosphorylation that might be expected to be functionally regulated by phosphorylation. 2,3-Butanedione monoxime (BDM) chemically removes phosphate groups from many proteins, and its action on DRK1 channels was examined after expression of DRK1 cRNA in Xenopus oocytes. In two-microelectrode voltage-clamp experiments, the application of 2,3-Butanedione monoxime to the bath inhibited DRK1 current (ki = 16.6 mM, H = 0.96) rapidly and reversibly, with a time course similar to the time course of solution change within the bath. DRK1 current was inhibited at all potentials; the time course of current activation, deactivation and inactivation were unaffected by 2,3-Butanedione monoxime. In inside-out patch-clamp experiments, the application of 2,3-Butanedione monoxime to the cytoplasmic surface similarly inhibited channel activity rapidly and reversibly (ki = 10.7 mM, H = 1.01) in the absence of rephosphorylating substrates. These results are inconsistent with a phosphatase effect, because such an effect should be irreversible in cell-free, ATP-free patches. Instead, the results suggest that 2,3-Butanedione monoxime can inhibit DRK1 channels directly from inside or outside of the membrane.
C7802 Charybdotoxin ≥90% (HPLC) High (BK) or intermediate (IK1) conductance calcium-activated and voltage-gated (Kv1.3) channel blocker.
Potent and selective inhibitor of the Ca2+-activated K+ channel present in GH3 anterior pituitary cells and primary bovine aortic smooth muscle cells.
C5856 Charybdotoxin, recombinant from Leiurus quinquestriatus hebraeus recombinant, expressed in E. coli, lyophilized powder Exhibits the same activity as the natural form of the toxin
C4397 Chlorzoxazone Chlorzoxazone is a skeletal muscle relaxant.
C2615 Chromanol 293B ≥98% (HPLC), powder Blocker of the slow delayed rectifier K+ current via KCNQ1 channels
C1618 Cibenzoline succinate ≥97% (NMR), solid Cibenzoline is a class IA antiarrhythmic drug. Cibenzoline (μM concentrations) blocks ATP-sensitive K channels in heart and pancreatic cells. Cibenzoline interacts with the channel pore-forming subunit of the K(ATP) channel (Kir6.2) from the cytoplasmic side. Cibenzoline also inhibits the delayed rectifier K current [I(Kr)] in sino-atrial node cells.
C2365 Clofilium tosylate >97%, solid K+ channel blocker; cardiac depressant; anti-arrhythmic
C6019 Clotrimazole Clotrimazole is a specific inhibitor of Ca2+-activated K+ channels. It is an antifungal azole. Clotrimazole is a derivative of imidazole and has similar antimicrobial action and activity to ketoconazole. It inhibits cytochrome P450-dependent 14α-demethylase, which is critical to ergosterol biosynthesis. The accumulated 14α-methylated sterols change the membrane structure of sensitive fungi, altering cell membrane permeability.
C2499 CP-339818 ≥98% (HPLC) CP-338818 blocks both Kv1.3 and Kv1.4. Kv1.3 is expressed in brain and in effector memory T (Tem) cells, and Kv1.4 is expressed in brain cells. Kv1.3 and Kv1.4 are members of the Shaker family of voltage-gated potassium channels. Both channels are involved in setting the membrane potential of neurons. In addition, Kv1.3 maintains the membrane potential for T memory cells and is up-regulated upon T cell activation, contributing to multiple immune processes and disorders. Blockers of Kv1.3 have long been sought for therapeutic benefit, and they are also valuable tools for studying the immune system. CP-339818 is valuable for immune system studies, where the absence of Kv1.4 makes it functionally selective for Kv1.3, and it has shown suppression of T cell activation. CP-339818 is also valuable for the study of Kv1.4 function.
C1055 Cromakalim Cromakalim is a compound that causes vasodilation by activation of potassium channels.
C5493 CyPPA ≥98% (HPLC), solid CyPPA is a positive modulator of small conductance Ca2+-activated K+ channels; selective for SK3 and SK2. CyPPA is a first subtype selective SK channel positive modulator with an EC50 of 5.6 μM and 14 μM, efficacy 90% and 71% for hSK3 and hSK2, respectively. CyPPA is a tool for distinguishing SK2 and SK3 from SK1 and IK; no other agents distinguish these channels.
D4438 β-Dendrotoxin ≥98% (SDS-PAGE), lyophilized powder  
D4813 Dendrotoxin-K ≥98% (HPLC), lyophilized powder Dendrotoxin-K inhibits potassium channels that contain Kv1.1 protein only.
D3768 Dequalinium chloride hydrate ≥95% (titration) Dequalinium chloride is a selective blocker of apamin-sensitive K+ channels and inhibitor of XIAP (X-linked inhibitor of apoptosis protein). Has been shown to induce cytotoxicity in human acute promyelocytic leukemia NB4 cells through disturbance of mitochondrial function, oxidative stress, and downregulation of Raf/MEK/ERK and PI3K/Akt signaling pathways.
D9035 Diazoxide Selective ATP-sensitive K+ channel activator in both vascular smooth muscle and pancreatic β-cells; antihypertensive.
D6942 DK-AH 269 ≥98% (HPLC), solid DK-AH 269 (Cilobradine) is an HCN Channel blocker; an open channel blocker of neuronal Ih and related cardiac If channels.
PZ0016 Dofetilide ≥98% (HPLC) Dofetilide is a Class III antiarrhythmic and hERG channel blocker. Dofetilide selectively blocks the rapid component of the delayed rectifier outward potassium current (IKr).
D7443 DPO-1 needles, >97% (NMR) DPO-1 is an inhibitor of human Kv1.5 potassium channel; representative blocker of a novel pharmacophore. The Kv1.5 potassium channel, which underlies the ultrarapid delayed rectifier current, IKur, is reported to be enriched in human atrium versus ventricle, and has been proposed as a target for novel atrial antiarrhythmic therapy. The administration of the IKur blocker (2-isopropyl-5-methyl-cyclohexyl) diphenylphosphine oxide (DPO-1) increases myocardial refractoriness in both atrium and ventricle of rat, but produces an atrial-selective increase in refractoriness in primates; appears to be 15-fold more selective for Kv1.5 vs Kv3.1 channels expressed in Xenopus oocytes. IC50 = 0.16-0.76 μM at 0.1 Hz pulsing frequency; Kd = 0.6 μM.
D9696 Dronedarone hydrochloride ≥98% (HPLC) Dronedarone is a Class III antiarrhythmic and a multi-channel blocker for atrial fibrillation. It blocks potassium, sodium, and calcium channels and also exhibits antiadrenergic properties.
M5060 E-4031 ≥98% (HPLC), solid E-4031 selectively blocks hERG K+ channels.
SML0034 1-EBIO ≥98% (HPLC) 1-EBIO is an activator of epithelial Ca2+-activated K+ channel also known as the intermediate-conductance Ca(2+)-activated K(+) channel (IK-1) or KCa3.1.
1-EBIO potentiates the secretion of CFTR-mediated Cl ion secretion by activating the basolateral KCNN4 K+ channels in native human colonic tissues. It stimulates the apical Cl channels and Ca+2-dependent basolateral K+ channels to stimulate fluid transport in lacrimal glands.
E9904 Ergtoxin from Centruroides noxius (Scorpion) recombinant, expressed in E. coli, >98% (HPLC), lyophilized powder A novel ERG1 (KV11.1) K+ channel blocker
SML0184 Ginsenoside Rg3 ≥98% (HPLC) Ginsenoside Rg3 is a natural product isolated from Panax ginseng. Similar to other ginsenosides it exhibits cardio protective effects. Ginsenoside Rg3 enhances cardiac, hERG (IKr) and KCNQ (Iks), channel currents by interaction with the channel pore entryway. It also inhibits the palmitate-induced apoptosis of MIN6N8 mouse insulinoma beta-cells through modulating p44/42 MAPK activation. Ginsenoside Rg3 increases the level of the transcription factor Nrf2 and induces the mRNA levels of multidrug resistance-associated protein (Mrp) 1 and Mrp3. Rg3 modulate neuroinflammation by attenuating the activation of microglia in response to systemic LPS treatment. It activates AMPK in HepG2 cells and reduces the lipid accumulation thereby decreasing the risk of cardiovascular disease due to dyslipidemia.
G2295 Glimepiride ≥98% (HPLC), solid Glimepiride is a potent blocker of cardiac KATP channels activated by pinacidil with an IC50 of 6.8 nM.
G117 Glipizide solid ATP-dependent K+ channel blocker.
G0639 Glybenclamide ≥99% (HPLC) Selectively blocks ATP-sensitive K+ channels; high affinity binding sites found in brain, pancreatic β cells, and cardiovascular system.
SML0135 GPV574 ≥98% (HPLC) GPV574 is a derivative of the Class 1C antiarrhythmic drug propafenone. GPV574 inhibits the delayed rectifier K+ channel HERG with similar affinity and time constant as propafenone (IC50 = 5 mM), but unlike the parent compound, does not remain permanently trapped in the channel pore. After wash-out of GPV574, channel activity is recovered within 60 seconds.
SML0403 GW542573X ≥98% (HPLC) GW542573X is a very selective activator of the small conductance calcium-activated potassium channel SK1 (KCa2.1).
SML1030 HENA ≥98% (HPLC) HENA (3-Hydroxyolean-12-en-30-oate) specifically activates large conductance, voltage- and Ca2+-gated K+ (BK) channels containing KCNMB1 (β1) subunits (EC50 = 53 μM). BK/β1 channels are expressed predominantly in smooth muscle. HENA induces vasodilation in rodent models.
SML1129 HUP30 ≥98% (HPLC) HUP30 is a potent vasodilating agent that stimulates soluble guanylyl cyclase, activate K+ channels, and blocks extracellular Ca2+ influx. Also, HUP30 directly modulates L-type Ca2+ channels.
H135 5-Hydroxydecanoic acid sodium salt ≥97% (HPLC) Blocks post-ischemic actions of the K+ channel activator cromakalim.
I5904 Iberiotoxin, recombinant from Mesobuthus tamulus ≥98% (HPLC), recombinant, expressed in E. coli Exhibits the same activity as the natural form of the toxin
The single chain peptide iberiotoxin (IbTX) is a selective and reversible inhibitor of high-conductance calcium-activated potassium channels (PK,Ca). It occurs naturally in the venom of the scorpion Buthus tamulus. IbTX also modulates the binding of charybdotoxin (CbTX) to smooth muscle sarcolemmal membranes in a non-competitive manner. IbTX is similar in size to CbTX and shares considerable sequence homology with CbTX. However, IbTX differs in its overall charge in having one fewer basic and four more acidic residues than CbTX.
I9910 Ibutilide hemifumarate salt ≥98% (HPLC) Ibutilide hemifumarate salt is considered a new generation "pure" Class III antiarrhythmic agent. Ibutilide binds to and alters the activity of hERG potassium channels, delayed inward rectifier potassium (IKr) channels and L-type (dihydropyridine sensitive) calcium channels.
SML1616 ICA-069673 ≥98% (HPLC) ICA-069673 is an orally active, potent and selective KV7.2/KV7.3 (KCNQ2/Q3) channel opener that is active in rodent epilepsy models.
I1661 ICA-105574 ≥98% (HPLC) hERG (Kv11.1) is a voltage-gated potassium channel with important cardiovascular function. Many potential and marketed drugs bind to and inhibit hERG function, causing prolongation of the electrocardiogram QT interval, which leads to life-threatening ventricular arrhythmias. Understanding of hERG function is critical for drug discovery and development. hERG exhibits a unique bell-shaped current-voltage relationship which is a result of very rapid inactivation of the channel upon voltage activation. ICA-105574 is a small molecule activator of hERG that binds to the channel to remove inactivation, thereby increasing peak current amplitude and shortening the action potential. It also modulates activation kinetics of the channel. ICA-105574 differs in efficacy, mechanism of action, and/or binding site from other known hERG activators and enhancers. This compound is a valuable tool for furthering understanding of hERG biophysics and physiology, expecially the structural transitions that occur during inactivation.
I2279 IMID-4F hydrochloride solid, solubility: >9 mg/mL in H2O, soluble Novel imidazoline-based K(ATP) channel blocker.
I6783 Isopimaric Acid ≥98% (GC), powder Potent opener of large conductance calcium activated K+ (BK) channels.
SML0281 Ivabradine hydrochloride ≥98% (HPLC) Ivabradine hydrochloride is an open channel blocker of neuronal I(h) and related cardiac I(f) channels, which are comprised of subunits of the hyperpolarisation-activated cyclic nucleotide-gated (HCN) channels, in particular HCN4. Ivabradine has antianginal activity. It lowers heart rate and reduces myocardial oxygen demand.
K3764 Kaliotoxin-1 recombinant, expressed in E. coli, ≥98% (HPLC), lyophilized powder Blocker of Ca2+-activated and voltage-gated (KV1.1 and KV1.3) potassium channels
SML1843 Kurarinone ≥98% (HPLC) New Kurarinone, a flavanone from Sophora flavescens roots, is a potent activator of the large-conductance calcium-activated potassium channel (BKCa channel). Kurarinone exhibits strong preference to potentiate the homomeric BKCa channel composed only of the α subunits. Kurarinone reduces acetylcholine induced contraction of rat urinary bladder strips and decreased the voiding frequency in a rat OAB model. Kurarinone exhibits cytotoxic and antiinflamatory activity. Kurarinone sensitizes TRAIL-induced tumor cell apoptosis via suppression of NF-KB-dependent cFLIP expression.
M8437 Margatoxin ≥99%, recombinant, expressed in E. coli Voltage-gated (Kv1.3) potassium channel blocker.
M8278 Margatoxin ≥90% (HPLC) Specific K(V)1.3 channel voltage-dependent K+ channel blocker
M7444 Maurotoxin recombinant, expressed in E. coli, ≥95% (HPLC), lyophilized powder Maurotoxin is a 34 amino acid recombinant toxin, originally isolated from the venom of the scorpion Scorpio Maurus palmatus; a member of the α-KTx6.2 scorpion toxin family. It blocks voltage-gated potassium channels (KV1.1/KCNA1, KV1.2/KCNA2, and KV1.3/KCNA3) and inhibits apamin-sensitive small conductance calcium-activated channels (SK channels), particularly KCa3.1(IKca1, SK4).
M7945 Mephetyl tetrazole ≥98% (HPLC), oil Mephetyl tetrazole is a potent and selective Kv1.5 potassium channel blocker. IC50 = 330 nM; shows selective atrial prolongation (40%) of effective refractory period (ERP), but no effect on ventricular ERP Kv1.5 channel is a molecular target for the treatment of atrial fibrillation.
M3189 Mepivacaine hydrochloride 98.0-102.0%, meets USP testing specifications Local anesthetic. Reversibly blocks transient Na+ inward current, as well as the steady-state K+ outward current. Blocks tandem pore (TASK) and Kv1.5, potassium channels in model systems.
SML1444 (±)-Mepivacaine hydrochloride ≥98% (HPLC) (±)-Mepivacaine hydrochloride is a local anesthetic that reversibly blocks transient Na+ inward current, as well as the steady-state K+ outward current. (±)-Mepivacaine blocks tandem pore (TASK) and Kv1.5 potassium channels in model systems.
M4145 Minoxidil ≥99% (TLC) Activates ATP-activated K+ channels; vasodilator; slow or stop hair loss and promote hair regrowth.
M7920 Minoxidil sulfate salt  
SML0190 ML133 hydrochloride ≥95% (HPLC) ML133 hydrochloride is a selective inhibitor of the Kir2 family of inward rectifier (IRK, KCNJ) potassium channels. ML133 inhibits Kir2.1 with IC50 of 1.8 μM at pH 7.4 and 290 nM at pH8.5. It exhibits little selectivity against other members of Kir2.x family channels, but has no effect on Kir1.1 (IC50 > 300 μM), and displays weak activity for Kir4.1 (76 μM) and Kir7.1 (33 μM), making ML133 the most selective small molecule inhibitor of the Kir family reported to date. It also showed modest selectivity versus hERG and a larger panel of GPCRs, ion channels and transporters.
SML0611 ML213 ≥98% (HPLC) ML213 is a selective opener of the potassium channels KCNQ2 and KCNQ4, with EC50 values of 230 and 510 nM, respectively.
SML0723 ML252 ≥98% (HPLC) ML252 is a potent, brain penetrant potassium channel Kv7.2 (KCNQ2) inhibitor with an IC50 of 69 nM. ML252 is only slightly selective over KCNQ3 and KCNQ4 but is over 40-fold selective for KCNQ2 vs KCNQ1, unlike other KCNQ inbhibitors currently used. ML252 was also selective vs. >68 tested GPCRs, ion channels, and transporters. Potassium channel Kv7.2 has become a new target for Alzheimer′s Disease drug research because inhibiting it enhances acetylcholine release. SAR studies showed a small structural change from ethyl group to hydrogen resulted in a functional shift from antagonist to agonist activity (37, EC50 of 170 nM), suggesting an interaction at a critical site for controlling KCNQ2 channel gating.
SML0524 ML277 ≥98% (HPLC) ML277 is a potent activator of KCNQ1 (Kv7.1) channels with >100-fold selectivity versus KCNQ2 and KCNQ4 and no activity against the hERG potassium channel up to 30 μM. KCNQ1 is a voltage-gated potassium channel required for repolarization phase of the cardiac action potential. Mutations in the KCNQ1 gene are associated with long QT syndrome (LQTS), a disorder in which the heart muscles take longer than normal to recover after each heart beat and can lead to dangerous arrhythmias such as atrial fibrillation. Activators of KCNQ1 channels could have potential use in treatments of LQTS. ML277 is the first selective and potent activator found, with an EC50 of 260 nM.
SML0836 ML297 ≥98% (HPLC) ML297 (VU0456810) is the first potent and selective activator of the GIRK potassium channel. The G protein-coupled inwardly-rectifying potassium channels (GIRKs 1-4) are widely distributed broadly in the central nervous system (GIRKs 1-3) and also found in the heart (GIRK-4). ML297 activates GIRK channels containing a GIRK1 subunit, and does not activate channels without a GIRK1 subunit or the closely related potassium channel Kir2.1 or voltage-gated potassium channels. ML297 has been shown to activate GIRK1/2 with a potency of ~160 nM and also to activate GIRK channels comprising of GIRK1/3 and GIRK1/4 subunit combinations. ML297 was active in two in vivo models of epilepsy, and showed equal or greater efficacy than the anti-seizure medication, sodium valproate.
SML0697 2-MMB ≥98% (HPLC) 2-MMB rescues the prolonged cardiac action potential in zebrafish carrying a mutation in the potassium channel KCNH2, that results in a condition that mimics long QT syndrome (LQTS).
N3539 Nicorandil ≥98% (HPLC) Nicorandil is a hybrid ATP-sensitive K+ (KATP) channel opener and nicotinamide nitrate NO donor. Nicorandil selectively activates SUR2B- versus SUR2A-containing KATP channels. It enhances endothelial NO synthase expression and protects against ischemic ventricular arrhythmias. By activating potassium channels, and donating nitric oxide to activate the enzyme guanylate cyclase, Nicorandil causes activation of GMP leading to both arterial and venous vasodilatation. Nicorandil is selective for vascular potassium channels, but has no significant action on cardiac contractility and conduction.
N135 S(+)-Niguldipine hydrochloride solid α1A-adrenoceptor antagonist; antihypertensive agent; L-type Ca2+ channel blocker; potassium agonist that activates Ca2+-activated maxi K-channels.
SML0553 NN414 ≥98% (HPLC) NN414 is a potent Kir6.2/SUR1 selective K-ATP channel opener. Activation of the pancreatic Kir6.2/SUR KATP channels inhibits insulin release to induce beta cell rest, reducing the workload of the beta cell which is thought may prove beneficial for patients with type 2 diabetes. A recent study found that NN414 also triggered burst-like discharges in substantia nigra dopamine neurons. These K-ATP channel enabled burst-like discharges are associated with novelty-dependent exploratory behavior and may also have relevance to Parkinson′s disease.
N0659 Noxiustoxin ≥95% (HPLC), recombinant, expressed in E. coli, lyophilized powder Blocks voltage-gated potassium channels.
SML0622 NS11021 ≥98% (HPLC) NS11021 is a potent, selective activator of the large conductance Ca2+-activated K+-channel, KCa1.1.
N170 NS 1619 powder Selective large conductance Ca2+-activated K+-channel activator.
N0663 NS1643 ≥98% (HPLC), solid The new diphenylurea compound 1,3-bis-(2-hydroxy-5-trifluoromethyl-phenyl)-urea (NS1643) was tested in hERG channel. In Xenopus laevis oocytes, NS1643 increased both steady-state and tail current at all voltages tested. The EC50 value for hERG channel activation was 10.5 μM. The effect could be reverted by application of the specific hERG channel inhibitor 4′-[[1-[2-(6-methyl-2-pyridyl)ethyl]-4-piperidinyl]carbonyl]-methanesulfonanilide (E-4031) at 100 nM. Application of NS1643 also resulted in a prolonged postrepolarization refractory time. hERG channel activation by small molecules such as NS1643 increases the repolarization reserve and presents a new antiarrhythmic approach.
N8161 NS309 ≥98% (HPLC), solid NS309 is a Ca2+-activated IK/SK potassium channel activator.
N2540 NS5806 ≥98% (HPLC) NS5806 increases peak current amplitude of the potassium channel Kv4.3 (EC50 = 5.3 uM). NS5806 also slows Kv4.3 and Kv4.2 current dacay in channel complexes containing KChIP2. In ventricular cardiomycytes, NS5806 increases transient outward current and reproduces the electrocardiographic profile of Brugada syndrome.
SML0745 NS6180 ≥98% (HPLC) NS6180 is a novel inhibitor of the intermediate-conductance Ca2+-activated K+ channel (KCa3.1) The IC50 of NS6180 against cloned human KCa3.1 is 9 nM. The compound blocks proliferation and production of IL-2 and IFNγ with sub-micromolar potencies in either ConA or PMA/ionomycin challenged rat splenocytes.
N2538 NS8593 hydrochloride ≥98% (HPLC), powder The compound (R)-N-(benzimidazol-2-yl)-1,2,3,4-tetrahydro-1-naphtylamine (NS8593) reversibly inhibited recombinant SK3-mediated currents (human and rat SK3) with potencies around 100 nM. NS8593 did not inhibit 125I-apamin binding. NS8593 decreased the calcium sensitivity by shifting the activation curve for Ca2+ to the right, only slightly affecting the maximal Ca2+-activated SK current. NS8593 inhibited all the SK1-3 subtypes Ca2+-dependently (Kd = 0.42, 0.60, and 0.73 μM, respectively, at 0.5 μM Ca2+. NS8593 did not affect the calcium-activated potassium channels of intermediate and large conductance (hIK and hBK channels, respectively). NS8593-mediated inhibition was prevented in the presence of a high concentration of the positive modulator NS309.
O104 Omeprazole solid Binds covalently to proton pump; inhibits gastric secretion.
P222 Pandinotoxin-Kα >99%, powder Pandinotoxin (PiTX) –Kα along with PiTX-Kβ and PiTXγ plays a vital role in blocking voltage-gated K+ channels.
P2928 Paxilline powder, ≥98% (HPLC) Selective blocker of high-conductance Ca2+-activated (Maxi-K) potassium channels
P5624 PD-118057 ≥98% (HPLC), solid PD-118057 is an activator of ether-a-go-go-related (hERG) potassium channel. PD-118057 is a second identified hERG channel activator, a representative in the series of structural analogs; PD-118057 at 10 μM leads to a 111% current increase in rabbit ventricular wedge (in comparison RPR260243 leads to only a 15% increase at the same concentration);PD-118057, unlike RPR260243, does not have a major effect on gating or kinetic properties of this channel. PD-118057prevents and reverses QT interval prolongation; Compounds such as PD-118057 may offer new approach in the treatment of delayed repolarization conditions, which occur in inherited or acquired long QT syndrome and congestive heart failure
P3053 Penitrem A ≥95% (HPLC and TLC) Tremorgenic fungal toxin; blocks high-conductance Ca2+-activated K+ channels.
PZ0278 PF-05020182 ≥98% (HPLC) PF-05020182 is a Kv7.2/4 potassium channel opener.
SML0835 PF74 ≥98% (HPLC) PF74 (PF-3450074) is a HIV-1 inhibitor that targets HIV capsid protein. PF74 binds specifically to HIV-1 particles and triggers premature HIV-1 uncoating in target cells.
P6124 5-(4-Phenoxybutoxy)psoralen ≥98% (HPLC), solid Selective inhibitor of Kv1.3, voltage-gated K+ channel. PAP-1 (EC50=2 nM) potently inhibits human T effector memory cell proliferation and delayed hypersensitivity. Effective orally or intraperitoneally. 5-(4-Phenoxybutoxy)psoralen has 23-fold selectivity for Kv1.3 over Kv1.5, and 33-125-fold selectivity over other Kv1 family channels.
P3584 L-α-Phosphatidyl-D-myo-inositol 4,5-diphosphate, dioctanoyl  
P3495 Phrixotoxin-2 >98% (HPLC), lyophilized powder Specific and reversible potassium Kv4.2 and Kv4.3 channel blocker. A natural peptide isolated from the tarantula Phrixotrichus auratus venom.
P154 Pinacidil monohydrate powder K+ channel activator; antihypertensive.
SML1326 PK-THPP ≥98% (HPLC) PK-THPP is a potent antagonist of tandem pore potassium channel subunit TASK-3 (KCNK9, K2P9.1) with an IC50 value of 35 nM for TASK-3 compared to 303 nM for TASK-1 and with >140 fold selectivity over a wider range of potassium channels. PK-THPP was found to act as a respiratory stimulant, stimulating breathing in isoflurane-anesthetized rats.
P9872 Psora-4 ≥98% (HPLC) The lymphocyte potassium channel Kv1.3 is regarded as a new target for immunosuppression. Psora-4 is the most potent small-molecule Kv1.3 blocker known. It blocked Kv1.3 in a use-dependent manner, with a Hill coefficient of 2 and an EC50 value of 3 nM, by preferentially binding to the C-type inactivated state of the channel. It exhibited 17- to 70-fold selectivity for Kv1.3 over closely related Kv1-family channels (Kv1.1, Kv1.2, Kv1.4, and Kv1.7) with the exception of Kv1.5 (EC50, 7.7 nM) and showed no effect on human ether-a-go-go-related channel, Kv3.1, the calcium-activated K+ channels (IKCa1, SK1-SK3, and BKCa), or the neuronal NaV1.2 channel. In a test of in vivo toxicity in rats, Psora-4 did not display any signs of acute toxicity after five daily subcutaneous injections at 33 mg/kg body weight. Psora-4 selectively suppressed the proliferation of human and rat myelin-specific effector memory T cells with EC50 values of 25 and 60 nM, respectively, without persistently suppressing peripheral blood naive and central memory T cells. Because autoantigen-specific effector memory T cells contribute to the pathogenesis of T cell-mediated autoimmune diseases such as multiple sclerosis, Psora-4 and other Kv1.3 blockers may be useful as immunomodulators for the therapy of autoimmune disord.
145904 Quinine 90% Potassium channel blocker
Q1250 Quinine hemisulfate salt monohydrate synthetic, ≥90% (HPLC) Potassium channel blocker. Antimalarial, anticholinergic, antihypertensive, and hypoglycemic agent; alkaloid originally isolated from the Cinchona family of South American trees. Inhibits mitochondrial ATP-regulated potassium channel. Used to study the metabolism of biocrystalized heme, hemozoin, in malarial parasites and to study the toxicity of heme (FP)-complexes.
Q1125 Quinine hydrochloride dihydrate Potassium channel blocker
SML1717 RA-2 ≥98% (HPLC) RA-2 is a selective pan-negative-gating modulator of KCa2/3 channels that potently inhibits both ex vivo and in vivo human KCa3.1 and all three human KCa2 channels subtypes. RA-2 right-shifts the KCa3.1 concentration-response curve for Ca2+-activation.
R9028 Repaglinide ≥98% (HPLC), solid Repaglinide is a potent short-acting insulin secretagogue that acts by closing ATP-sensitive potassium (KATP) channels in the plasma membrane of the pancreatic beta cell. It represents a new class of insulin secretagogues, structurally unrelated to sulphonylureas, which were developed for the treatment of type 2 diabetes.
SML0325 Retigabine ≥98% (HPLC) Retigabine (Ezogabine) is a Kv7.2-7.5 (KCNQ2-5) neuronal potassium channel opener witrh anticonvulsant activity.
SML1738 RL648_81 ≥98% (HPLC) RL648_81 is a selective and potent KCNQ2/3 channel activator.
R3277 Rutaecarpine >98% (HPLC) Delayed rectifier K+ channel blocker. Inhibits platelet aggregation; vasoldilator.
S6444 N-Salicyloyltryptamine ≥98% (HPLC), solid N-Salicyloyltryptamine (STP) is a central nervous system depressant that inhibits the transient outward and sustained K+ current in neuroendocrine cells. This decreases the ability of neuronal cells to generate action potential.1,3 STP is has immunomodulatory effects as it inhibits the activation of ERK 1/2 and NF-κB.4
Activator of calcium-activated K+ channels; anticonvulsant and neuroprotectant.
S0323 Sematilide monohydrochloride monohydrate ≥99% (HPLC), white solid Sematilide monohydrochloride monohydrate is a class III antiarrhythmic; selective delayed rectifier K+ current (IKr) channel blocker. It inhibits rapidly activating Ik in guinea pig atrial myocytes, resulting in the prolongation of action potential duration and refractoriness; shows proarrhythmic effects and may lead to QT interval prolongation.
S6193 SG-209 solid, ≥98% (HPLC) Potassium channel activator; analog of nicorandil; nitrate-free coronary vasodilator
SG-209, a derivative of nicorandil, opens up potassium channels and leads to vasodilation. It dilates tracheal smooth muscle and increases the blood flow to the trachea in dogs.3
LO2220 Sodium/Potassium Channel Modulators Ligand Set ligand set for potassium/sodium channel modulators, exchangers, cotransporters, ionophores and ion pumps  
SML1500 Spadin trifluoroacetate salt ≥95% (HPLC) Spadin is a brain penetrant TREK-1 channel inhibitor that has antidepressant effects in mouse models of depression with a rapid onset of action.
T3326 Tamapin recombinant, expressed in E. coli, ≥95% (HPLC), lyophilized powder Member of the α-5.4 scorpion toxin family. Blocks KCa2 channels with selectivity for KCa2.2 versus KCa2.1 channels.
Tamapin strongly associates with Ca(2+)-activated K(+) (SK) channels and blocks SK-channel mediated currents in hippocampal neurons1.
T8316 Tertiapin >95% A potent inhibitor of the inward-rectifier K+ channels, blocked a G-protein-gated channel (GIRK1/4) and the ROMK1 channel with nanomolar affinities, however a closely related channel, IRK1, was insensitive to tertiapin. Thus, tertiapin is a tool for purifying functional channels as well as for screening pharmaceutical agents against these channels.
Tertiapin is a peptide isolated from honey bee venom, which is a selective IKACh blocker that prolongs the atrial effective refractory period and terminates the atrial fibrillation. It is a selective and potent inhibitor of muscarinic K+ channels in rabbit cardiac myocytes.
T1567 Tertiapin-Q trifluoroacetate salt ≥97% (HPLC) Blocks the GIRK1/4 and ROMK1 members of the inward-rectifier K+ channel family.
T7383 Tetracaine ≥98% (TLC) Blocks voltage-sensitive release of Ca2+ from sarcoplasmic reticulum.
Tetracaine also refers as 4-(Butylamino)benzoic acid 2-(dimethylamino)ethyl ester interfere with calcium movement in muscle and non-muscle cells and can inhibit potassium-induced as well as caffeine-induced shortening of outer hair cells (OHC′s). But, the product can′t inhibit electrically-induced shortening of OHC′s.The product can also stimulate caspase activation and inhibits pro-survival signalling pathways which in turn induce human renal cell apoptosis.
T7508 Tetracaine hydrochloride ≥99% Blocks voltage-sensitive release of Ca2+ from sarcoplasmic reticulum.
T2265 Tetraethylammonium chloride ≥98% (titration) Blocks K+ channels; blocks nicotinic acetylcholine neurotransmission by blocking the receptor-mediated K+ currents.
T6700 TRAM-34 ≥98% (HPLC), solid TRAM-34 exhibits 100-fold selectivity (Kd = 20 nM) for IKCa1 channels over other K+ channels (Charybdotoxin, Kd = 5 nM, Clotrimazole, Kd = 70 nM; Nitrendipine Kd = 900 nM). Furthermore, TRAM-34 is known to suppress the activation of human T lymphocytes,.
TRAM-34 is a potent inhibitor of the intermediate-conductance Ca2+-activated K+ channel.
U8881 UCL 1684 ditrifluoroacetate hydrate UCL 1684 ditrifluoroacetate hydrate is a potent non-peptide blocker of the apamin-sensitive Ca2+-activated K+ channel.
U5883 UCL-1848 trifluoroacetate salt ≥98% (HPLC), solid Selective Ca2+-activated, SK potassium channel blocker
U3885 UK-78282 monohydrochloride ≥98% (HPLC) UK-78282 blocks both Kv1.3 and Kv1.4. Kv1.3 and Kv1.4 are members of the Shaker family of voltage-gated potassium channels. Kv1.3 is expressed in brain and in effector memory T (Tem) cells, and Kv1.4 is expressed in brain. Both channels are involved in setting the membrane potential of neurons. In addition, Kv1.3 maintains the membrane potential for T memory cells and is up-regulated upon T cell activation, contributing to multiple immune processes and disorders. Blockers of Kv1.3 have long been sought for therapeutic benefit, and they are also valuable tools for studying the immune system. Selective blockers of Kv1.4 are desired, as there are few if any currently available. UK-78282 is valuable for immune system studies, where the absence of Kv1.4 makes it functionally selective for Kv1.3, and it has shown suppression of T cell activation. UK-78282 is also valuable for the study of Kv1.4 function.
SML1142 VU0071063 ≥98% (HPLC) VU0071063 is a potent activator of Kir6.2/SUR1 KATP channels (EC50 = 10.3 μM). VU0071063 reversibly inhibits glucose-stimulated calcium influx in mouse β-islet cells. The compound VU0071063 has no affect on Kir6.2/SUR2A channels.
SML0672 VU0405601 ≥98% (HPLC) VU0405601 is a hERG (the human Ether-à-go-go-Related Gene) agonist that increased the IC50 of dofetilide from 38.7 nM to 76.3 nM. VU0405601 protects against arrhythmias induced by hERG inhibition.
V4265 VU 590 dihydrochloride hydrate ≥ (HPLC) VU590 inhibits ROMK at sub-micromolar affinity (294 nM) and Kir7.1 at low micromolar affinity, but it does not inhibit Kir2.1 or Kir4.1. VU590 appears to act by blocking the ion permeation pathway of the channel.
SML0077 VU591 ≥98% (HPLC) VU591 is a Potassium Inwardly-Rectifying Channel (KCNJ1 or ROMK) specific inhibitor (IC50 = 240 nM) that is closely related to VU590. Unlike VU590, VU591 does not inhibit Kir7.1. The compound has a modest effect on Kir6.2/SUR1, causing 17% inhibition at 10 uM.
X2254 XE-991 ≥98% (HPLC) XE-991 is a KCNQ channel blocker; which is more potent than linopiridine (Cat. No. L-134).
SML1558 Yoda1 ≥98% (HPLC) Yoda1 is a specific activator of mouse and human cation channel Piezo1, a mechanosensitive channel that mediates Ca2+ influx on mechanical activation and has been linked to a role in blood vessel development. Yoda1 stabilizes the Piezo1 open channel. In red blood cells, this was followed by downstream activation of the KCa3.1 Gardos channel with resultant calcium influx and potassium and water efflux, causing shrinkage of the cells. Yoda1 is the first Piezo1 agonist, giving the first evidence of non-mechanical activation of a Piezo channel.
Z0127 Zatebradine hydrochloride ≥98% (HPLC), powder HCN channel blocker: blocker of neuronal Ih, related cardiac If channels and ATP-sensitive Kir channels.
Z3777 ZD7288 hydrate ≥98% (HPLC) Selective blocker of cation channel Ih; If blocker and sino-atrial node function modulator, blocks hyperpolarization-activated and cyclic nucleotide-gated (HCN) channels.