Receptor expression is a research area that focuses on studying the presence and levels of specific receptors on cells or tissues. Receptors are proteins on the surface of cells that interact with signaling molecules such as hormones or neurotransmitters, triggering a specific cellular response. Receptor expression research involves identifying and quantifying the types and amounts of receptors present in different cell types or tissues, and investigating how changes in receptor expression may affect cellular functions, signaling pathways, and disease processes. This research can provide insights into the mechanisms underlying various physiological and pathological conditions, and may guide the development of novel therapeutic strategies targeting specific receptors.