Overview
- Hougaard, C. et al. (2007) Br J. Pharmacol. 151, 655.
Alomone Labs CyPPA enhances hSK2 channel currents in transiently transfected HEK293T cells.Cells were stimulated with 100 μM CyPPA (#C-110) and currents were measured using whole cell voltage-clamp. A. Time course at -20mV showing the effect of 100 μM CyPPA and its inhibition with 150 nM Apamin (#STA-200). B. Representative currents at control conditions (bottom) and following application of 100 μM CyPPA (top). Currents were elicited by a 150 ms voltage ramp from -120 to 60 mV every 10 seconds from a holding potential of -80 mV (current responses are shown between -120 and -10 mV). Leaks were subtracted offline.
Ca2+-activated potassium channels (KCa) are a group of 6/7-TM ion channels that selectively transport K+ ions across biological membranes. They are broadly classified into three subtypes: SK, IK and BK channels (small, intermediate and big conductance).
Small-conductance Ca2+-activated K+ channels (SK channels) underlie the medium duration after hyperpolarization that follows single or trains of action potentials in many types of neurons. This family is composed of KCa2.1 (SK1), -2.2 (SK2), and -2.3 (SK3) isoforms, which are expressed differentially within the central nervous system (CNS)1,2.
CyPPA is an activator of small conductance KCa channels that displays selectivity for SK2 and SK3 channels (EC50 values are 5.6 and 14 µM for SK3 and SK2 respectively and efficacy is 90% and 71% for hSK3 and hSK2, respectively)3. CyPPA displays no activity at SK1 and IK (KCa3.1) channels3.
CyPPA is a tool for distinguishing SK2 and SK3 from SK1 and IK; no other agents distinguish these channels from one another. Therefore, it enriches the repertoire of tools available to test the hypothesis that SK channels may be targets for future CNS drugs4.
CyPPA was found to block TRPM7 channels, demonstrating an overlap between pharmacological compounds acting on TRP and KCa channels5.
