Receptor functions

Prescribers should have some understanding of receptor mechanisms because many drugs commonly used in modern practice act on receptors, safe drug usage requires an understanding of receptor pharmacology and future advances in pharmacology and therapeutics are likely to develop from the discovery of further receptors and molecular modelling of drugs to interact with them. This article covers basic concepts such as receptors and ligands, agonists and antagonists, dose–response curves, efficacy, potency, selectivity and affinity. It illustrates the different ways that ligand–receptor interactions can be coupled to responses (e.g. channel-linked receptors, G-protein-coupled receptors, kinase-linked receptors and receptors regulating gene transcription). The potential for agonists, partial agonists and antagonists to interact with each other is examined. The importance of understanding the dose–response curve, and its influence on the likelihood of achieving clinical efficacy without causing adverse effects, is emphasized.