Sodium/calcium exchangers are neuronal plasma membrane transporters, which by coupling Ca2+ and Na+ fluxes, may play a relevant role in brain ischemia. The exchanger gene superfamily comprises two arms: the K +-independent (NCX) and K+-dependent (NCKX) exchangers. In the brain, three different NCX (NCX1, NCX2, NCX3) and three NCKX (NCKX2, NCKX3, NCKX4) family members have been described. Up to now, no sutides about the role played by NCKX proteins in cerebral ischemia have been published. The aim of the present study was to investigate the role of NCKX2 in an in vivo model of permanent middle cerebral artery occlusion (pMCAO). The role of this protein in the development of ischemic damage was assessed by knocking-down its expression with an antisense oligodeoxynucleotide (AS-ODN), intra-cerebroventricularly infused by an osmotic minipump for 48 h, starting from 24 h before pMCAO. The results showed that NCKX2 knocking-down by using antisense strategy increased the extent of the ischemic lesion. The results of this study suggest that NCKX2 could exert a neuroprotective effect during ischemic injury.