agonizm

Agonism is a term used in pharmacology to describe a substance that binds to a receptor and elicits a biological response. This response is typically proportional to the degree of receptor occupancy. Agonists can be classified into full agonists, which produce the maximum possible response, and partial agonists, which produce a submaximal response even when all receptors are occupied. The efficacy of an agonist refers to its ability to activate the receptor and produce a response.

Agonists work by mimicking the action of endogenous ligands, which are naturally occurring molecules in the body that bind to receptors. For example, acetylcholine is an endogenous agonist at muscarinic receptors, and it elicits a variety of physiological responses. In pharmacology, agonists are often used therapeutically to treat diseases by either stimulating a deficient pathway or by activating a receptor that is not being adequately stimulated.

The interaction between an agonist and its receptor is often described by the law of mass action, which states that the rate of a reaction is proportional to the concentration of the reactants. In the context of receptor binding, this means that the higher the concentration of the agonist, the more receptors will be occupied, and the greater the biological response. The potency of an agonist refers to the concentration of the drug required to produce a given effect, often measured as the EC50, which is the concentration of agonist that produces 50% of the maximal response.