Zinc-Permeable Ion Channels: Effects on Intracellular Zinc Dynamics and Potential Physiological/Pathophysiological Significance

Author(s):

Koichi Inoue, Zaven O`Bryant and Zhi-Gang Xiong   Pages 1248 - 1257 ( 10 )

Abstract:

Zinc (Zn²⁺) is one of the most important trace metals in the body. It is necessary for the normal function of a large number of protein s including enzymes and transcription factors. While extracellular fluid may contain up to micromolar Zn²⁺, intracellular Zn²⁺ concentration is generally maintained at a subnanomolar level; this steep gradient across the cell membrane is primarily attributable to Zn²⁺ extrusion by Zn²⁺ transporting systems. Interestingly, systematic investigation has revealed that activities, previously believed to be dependent on calcium (Ca²⁺), may be partially mediated by Zn²⁺. This is also supported by new findings that some Ca²⁺-permeable channels such as voltage-dependent calcium channels (VDCCs), N-methyl-D-aspartate receptors (NMDA), and amino-3- hydroxy-5-methyl-4-isoxazolepropionate receptors (AMPA-Rs) are also permeable to Zn²⁺. Thus, the importance of Zn²⁺ in physiological and pathophysiological processes is now more widely appreciated. In this review, we describe Zn²⁺- permeable membrane molecules, especially Zn²⁺-permeable ion channels, in intracellular Zn²⁺dynamics and Zn²⁺ mediated physiology/pathophysiology.

Keywords:

Calcium, fluorescence imaging, ion channel, zinc.

Affiliation:

Neuroscience Institute, Morehouse School of Medicine, Atlanta, USA.

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