Overview
- Bentzen, B.H. et al. (2007) Mol. Pharmacol. 72, 1033.
Alomone Labs NS-11021 activates KCa1.1 channels expressed in Xenopus oocytes.A. Time course of normalized KCa1.1 currents at +50 mV. Currents were elicited by 150 ms voltage ramp from holding potential of -100 mV to +100 mV every 10 sec. NS-11021 (#N-335), applied at 2 µM and 10 µM, as indicated (bars), reversibly enhanced KCa1.1 currents. B. Current traces upon application of control, or of 2 µM and 10 µM NS-11021 (as indicated).
NS-11021 is a synthetic, potent and selective activator of KCa1.1 - the large conductance Ca2+-activated K+-channel with an EC50 value of 0.4 µM KCa1.1. NS-11021 affects KCa1.1 in both their open and closed states. Application of NS-11021 (3 µM) increased Kca1.1 currents by 171±31% for channels that shift between open and closed state and by 187±27% for channels kept in closed conformation in Xenopus oocytes heterologously expressing hKCa1.1. NS-11021 also produces a negative shift in the threshold for current activation and increases the peak tail current amplitude for KCa1.1 channels. NS-11021 also activates the KCNQ4 (KV7.4) channel at high concentrations but has a minor or no effect on other potassium and calcium channels. NS-11021 is effective when exposed to either side of the cell’s membrane and most likely exerts its effect through direct binding to the KCa1.1 α-subunit1.
