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

[ Vol. 22 , Issue. 10 ]

Author(s):

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

Abstract:


Zinc (Zn<sup>2+</sup>) 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 Zn<sup>2+</sup>, intracellular Zn<sup>2+</sup> concentration is generally maintained at a subnanomolar level; this steep gradient across the cell membrane is primarily attributable to Zn<sup>2+</sup> extrusion by Zn<sup>2+</sup> transporting systems. Interestingly, systematic investigation has revealed that activities, previously believed to be dependent on calcium (Ca<sup>2+</sup>), may be partially mediated by Zn<sup>2+</sup>. This is also supported by new findings that some Ca<sup>2+</sup>-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 Zn<sup>2+</sup>. Thus, the importance of Zn<sup>2+</sup> in physiological and pathophysiological processes is now more widely appreciated. In this review, we describe Zn<sup>2+</sup>- permeable membrane molecules, especially Zn<sup>2+</sup>-permeable ion channels, in intracellular Zn<sup>2+</sup>dynamics and Zn<sup>2+</sup> mediated physiology/pathophysiology.

Keywords:

Calcium, fluorescence imaging, ion channel, zinc.

Affiliation:

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



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