Validation of the RNAscope method using a positive and a negative control probes. A–B. In situ hybridization was performed with an RNAscope probe targeting the eukaryotic housekeeping gene Ppib (i.e., positive control). The hippocampal section was made from a CB2R WT mouse and the images were taken from the CA1 region (A) and dentate gyrus (B). C–
D. The RNAscope hybridization was conducted with a negative control probe targeting the bacterial gene DapB. The CA1 region (C) and dentate gyrus (D) were imaged from a hippocampal slice cut from a WT mouse. pyr, stratum pyramidale; rad, stratum radiatum; mol, stratum moleculare; gra, stratum granulosum; hil, hilus.