Zn2+ transporters and Zn2+ homeostasis in neurons.

Although the presence of Zn2+ in the brain has been known for nearly half a century, only recently has its precise location and potential roles as a neuromodulator and signaling molecule as well as neurotoxic agent come to the forefront. Unfortunately, our understanding of Zn2+ homeostatic mechanisms lags far behind. The recent identification of presumed Zn2+ transporters has opened new approaches to studying Zn2+ homeostatic mechanisms in neurons. Zn2+ transporters are involved in separate Zn2+ influx and efflux pathways in neurons. However, we are only beginning to understand the mechanism of Zn2+ transport and much more research needs to be done. We are only beginning to understand the transcriptional control and cellular location of Zn2+ transporters, as well. Finally, this review presents a working model of neuronal Zn2+ homeostasis and discusses the experimental evidence for the proposed roles that Zn2+ transporters might play.