Zinc reduces low-threshold Ca2+ currents of rat thalamic relay neurons

Abstract

Whole-cell voltage-clamping of thalamic relay neurons was used to examine the possibility of a Zn2+-mediated reduction of the low-threshold transient Ca2+ current (IT) of a central element in thalamocortical oscillations. We found that Zn2+ reversibly decreased IT in a concentration-dependent manner (IC50=55 μM), mainly by reducing the number of IT channels available for activation. Zn2+ did not affect the reaction kinetics, but did affect the voltage-dependence of IT channel gating. However, the apparent alterations in gating properties were not enough to account for the huge IT reduction. © 2003 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.