Receptor agonists are molecules that activate specific receptors in the body, leading to a biological response. These agonists can mimic the action of natural ligands that bind to the receptors, resulting in the activation of signaling pathways and physiological effects. Receptor agonists are commonly used in pharmacology and drug development to target specific receptors and modulate their functions for therapeutic purposes. They are also utilized in research to study the roles and mechanisms of various receptors in biological processes. Overall, receptor agonists play a crucial role in understanding receptor-mediated signaling and developing new treatments for various diseases.