Figure 1.

PAC1 is expressed in mouse and rat brain. A, Representative image showing the PAC1 mRNA expression in various mouse and rat brain regions, and in cultured rat hippocampal neurons (CHN) from RT-PCR analysis using specific primers spanning the variable region of PAC1. The Null, Hop1 and Hop2 isoforms were identified based on transcript size, followed by sequencing of the specific PCR products. cDNAs of mouse PAC1-Null, PAC1-Hop1 and PAC1-Hop2 were used as positive controls in these RT-PCR experiments. Numbers on the left denote the relative mobility of molecular weight markers. B, Representative confocal photomicrographs of the hippocampal formation in sections from mouse brain (40 μm; sagittal) immunostained with antibodies against Kv4.2 (green) and PAC1 (red), and DAPI (blue). Kv4.2 is expressed predominantly in the outer molecular layer of the dentate gyrus, as well as in stratum oriens and stratum radiatum layers, which contain the distal dendrites of neurons in CA1 and CA3 regions (magnified images shown in middle and bottom rows. PAC1 immunoreactivity is more intense in the outer molecular layer of the dentate gyrus, followed by CA1 and CA3 pyramidal cell body and dendritic layers. Images on the right column of each row are taken from mouse brain sections that were incubated only with the same secondary antibodies (2° Ab.) and DAPI, without the primary antibodies against Kv4.2 and PAC1. Scale bar – 100 μm for images in the top row (magnification: 10×), and 25 μm for middle- and bottom-row images (magnification: 63×).