In histology, GPCRs are studied using various techniques to understand their distribution, density, and functional role in different tissues. Techniques such as immunohistochemistry (IHC), in situ hybridization (ISH), and fluorescence microscopy are commonly used to visualize and quantify GPCR expression in tissue sections. These methods utilize specific antibodies or probes that bind to GPCRs or their mRNA, allowing researchers to observe their localization and abundance.