Rationale: Ultrastructural localization of NCX1 in the cerebral cortex and hippocampus CA1. Preembedding immunoperoxidase and silver-enhanced immunogold procedures were used. Figure 4b shows NCX1 immunoparticles associated to microtubules, mitochondria, and plasma membrane in several dendritic profiles. Figure 4C shows dendritic spines labelled by the DAB reaction, indicating expression of NCX1. The corresponding axons are not labelled. Figure 4D - particles associated with the membrane in the vicinity of the PSD in the CA1 stratum radiatum. Table 1 presents a quantification of the immunolabeling, and shows that a large portion of NCX1 profiles the cerebral cortex and in the hippocampus are in dendrites and spines. Antibody:'NCX1 protein was detected by using a commercially available mouse monoclonal IgG antibody (R3F1; Swant, Bellinzona, Switzerland)'. Figure 1 demonstrated antibody specificity in western blotting of hippocampus, heart and cortex homogenates in comparison with a recombinant protein produced in HEK cells. Strong WB signals with little cross-reactivity are a good indication for the antibody specificity.. Experimental description: 'Sprague–Dawley male adult albino rats (200–300 g) were used in these studies'