Referenced in: none

Automatically associated channels: Kir2.1

Title: [The blocking effects of extracellular Mn2+ on the inward rectifier potassium channel (IRK1)]

Authors: A Xie, Y M Zang, M Z Zhu

Journal, date & volume: Zhongguo Ying Yong Sheng Li Xue Za Zhi, 2000 Nov , 16, 331-4

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/11236692

Abstract
Two-microelectrode voltage clamp (TEV) method was used to study the blocking effects of extracellular Mn2+ on the inward rectifier potassium channel (IRK1) expressed in the Xenopus oocytes.Mn2+ can concentration-, time- and vol-tage dependently block IRK1 instantaneous currents (2 ms after voltage applied). Mn2+ has almost no effect on the gating property of IRK1. IRK1 can not permeate Mn2+ because reverse potential did not changed. External Mn2+ can inhibit IRK1 macroscopic currents more powerfully when external Mn2+ concentration is lower and external Mn2+ can increases standard chord conductance of IRK1.External Mn2+ works through surface potential mechanism. Ba2+ is considered as one fast open channel blocker of IRK1 and three exponential fitting results indicates that external Mn2+ can compete with Ba2+ in the same binding site in IRK1 when external Ba2+ concentration is 30 mumol/L. These mean two different mechanisms about external Mn2+ blocking exist.