Exp Neurobiol 2005; 14(1): 5-9

Published online July 1, 2005

© The Korean Society for Brain and Neural Sciences

Zinc Defers the Initiation of a Phasic Burst-type Firing of Rat Thalamic Relay Neurons

Min-Jung Shin and Jun-Mo Chung*

Department of Life Sciences and Center for Cell Signaling Research (CCSR), Ewha Womans University, Seoul 120-750, Korea

Correspondence to: *To whom correspondence should be addressed.
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A visualized whole-cell voltage clamping of thalamic slices was used to examine the possibility of a Zn2+-mediated alteration of Ca2+-dependent burst firing of a central element in thalamocortical oscillation. We found that Zn2+ reversibly delayed the initiation of low-threshold spike (LTS), a base of the burst firing, only when the membrane potentials of a thalamic neuron were more positive than -65 mV. A hyperpolarization- activated cationic current (Ih), one of the central ionic conductances in determining LTS generation, was decreased by Zn2+. However, the effective membrane potential range of the zinc action was below -75 mV so that the Zn2+ effect on Ih should not account for the LTS delay. We thus propose here that a transient low threshold Ca2+ current and/or a transient K+ current must be main determinants for the LTS delay by Zn2+.

Keywords: H-current, oscillation, slice recording, thalamocortical pathway