👉 The receptor fluid, also known as the receptor microenvironment or receptor milieu, refers to the dynamic and complex network of molecules surrounding and interacting with receptors on cell surfaces. This fluid encompasses various components such as lipids, proteins, ions, and other signaling molecules that are not part of the receptor itself but play a crucial role in its function. These components can modulate receptor activity, influence receptor conformation, and facilitate or inhibit receptor-ligand interactions. The receptor fluid is essential for proper signal transduction, as it provides the necessary context and conditions for receptors to effectively respond to their ligands, ensuring precise and regulated cellular responses.