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Updated: Apr 27, 2026

High-throughput Screening for Small-molecule Modulators of Inward Rectifier Potassium Channels
Published on: January 27, 2013
New positive Ca2+-activated K+ channel gating modulators with selectivity for KCa3.1.
Nichole Coleman1, Brandon M Brown1, Aida Oliván-Viguera1
1Department of Pharmacology (N.C., B.M.B., V.S., H.W.), School of Medicine, and Department of Chemistry (M.M.O.), University of California, Davis, California; Aragon Institute of Health Sciences, Instituto de Investigación Sanitaria, Fundación Agencia Aragonesa para la Investigación y el Desarrollo, Zaragoza, Spain (A.O.-V., R.K.); and Grupo de Investigación del Medio Ambiente del Centro de Estudios Superiores, Faculty of Health Sciences, Universidad San Jorge, Villanueva de Gállego, Spain (M.S.V.).
Researchers developed novel compounds, SKA-111 and SKA-121, that selectively activate intermediate-conductance (KCa3.1) calcium-activated potassium channels. SKA-121 demonstrates therapeutic potential for KCa3.1 activation by lowering blood pressure in mice.
Area of Science:
- Molecular Biology
- Pharmacology
- Cardiovascular Research
Background:
- Small-conductance (KCa2) and intermediate-conductance (KCa3.1) calcium-activated potassium channels share gating mechanisms.
- Existing modulators often lack selectivity, activating both channel types.
- Optimizing KCa3.1-selective modulators is crucial for therapeutic applications.
Purpose of the Study:
- To optimize the benzothiazole pharmacophore of SKA-31 for KCa3.1 selectivity.
- To identify novel positive gating modulators with enhanced KCa3.1 specificity.
- To evaluate the in vivo efficacy and pharmacokinetic properties of novel compounds.
Main Methods:
- Structure-activity relationship (SAR) study of benzothiazole derivatives.
- In vitro electrophysiology to assess channel activation and selectivity.
- In vivo blood pressure telemetry in wild-type and KCa3.1 knockout mice.
- Pharmacokinetic studies to determine half-life and brain penetration.
Main Results:
- Identified SKA-111 and SKA-121 with high selectivity for KCa3.1 over KCa2 channels.
- SKA-121 showed 41-fold selectivity for KCa3.1 (EC50 109 nM) over KCa2.3 (EC50 4.4 μM).
- SKA-121 significantly reduced mean arterial blood pressure in mice, an effect absent in KCa3.1(-/-) mice.
- SKA-111 exhibited longer half-life and brain penetration, lowering blood pressure and heart rate.
Conclusions:
- SKA-121 is a potent and selective KCa3.1 positive gating modulator.
- SKA-121 demonstrates therapeutic potential for conditions treatable by KCa3.1 activation, such as hypertension.
- Further exploration of SKA-121 is warranted for its therapeutic applications.
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