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Updated: Oct 9, 2026
Study of the Functions and Activities of Neuronal K-Cl Co-Transporter KCC2 Using Western Blotting
Published on: December 9, 2022
Possible underestimation of the channel conductance underlying pinacidil-induced K+ currents using noise analysis in
N Teramoto1, A F Brading, Y Ito
1Department of Pharmacology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan. noritera@linne.med.kyushu-u.ac.jp
Abstract:
Electrophysiological and pharmacological properties of the pinacidil-induced K+ currents in isolated cells from pig urethra were investigated using patch-clamp techniques. Pinacidil (100 microM) induced an outward current at -50 mV which gradually decreased. Under current-clamp conditions, 100 microM pinacidil induced a hyperpolarization that was sustained. This suggests that activation of only a few channels can hyperpolarize the membrane. At a holding potential of -50 mV, glibenclamide inhibited the pinacidil-induced current with a single exponential time course. Unitary current recordings in symmetrical 140 mM K+ conditions demonstrated that pinacidil activates a 43-pS, glibenclamide-sensitive K+ channel (i.e. K(ATP) channel). Analysis of the basal noise of the pinacidil-induced macroscopic currents from -90 mV to -30 mV yielded estimates of channel conductance (6 pS) which were much smaller, and probably an underestimate. These results indicate that pinacidil induces a glibenclamide-sensitive K+ current through only one type of K+ channel (K(ATP) channel) in pig urethra.
