GENE-EXPRESSION OF NA+ CA2+ EXCHANGER IN BRAIN ISCHEMIA/

It is known that intracellular Ca2+ is overloaded during ischemia as a result of the altered activity of the Na+/Ca2+ exchanger, one of the major pathways of Ca2+ efflux. But the molecular mechanism of the alte ration is still unknown. We cloned a -500bp cDNA fragment of rat cereb ellar Na+/Ca2+ exchanger gene. Using this cDNA fragment as the probe, we found that the Na+/Ca2+ exchanger mRNA is widely distributed in rat central and peripheral nervous system such as in cerebra, heart, lung and kidney. Using focal cerebal ischemic model, we detected the gene expression of Na+/Ca2+ exchanger in ischemic brain by Northern bolt an d in situ hybridization, and found that in ischemic tissues, the mRNA level of Na+/Ca2+ exchanger is lowered.