Figure 1. By light microscopy, GPER1-IR is detected throughout the dorsal mouse hippocampus. A, At low-magnification, diffuse GPER1-IR is densest in the pyramidal cell layer (especially CA3), cells interspersed in SO of CA1 and CA3, stratum lucidum of CA3 and the hilus of the dentate gyrus (DG). B, At higher-magnification, GPER1-IR is seen in CA1 pyramidal cells (pcl), as well as dendritic processes in stratum radiatum (SR). C, High-magnification also reveals several GPER1-IR neurons in the hilus (hil) of the DH. D, In the CA3, many GPER1-IR terminals are found in the stratum radiatum and stratum lucidum (SLu) and surrounding cell bodies in the pyramidal cell layer. E, No labeling was seen in any of these regions following preadsorption of the GPER1 antibody with the antigenic peptide. F, GPER1-IR was greatly reduced in the hippocampus of mice carrying a GPER1-null mutation. However, some GPER1-IR remained in stratum lucidum of CA3. Scale bars: A, E, F, 500 μm; B, C, D, 100 μm.