Bradykinin

Part of speech: noun

Definitions

1. A peptide that causes blood vessels to dilate, leading to lowered blood pressure and increased permeability; it acts as a mediator of inflammation and pain; involved in various physiological and pathological processes in the body
2. A biologically active compound that promotes vasodilation and vascular permeability, contributing to inflammatory responses and transmitting pain signals; it plays a role in cardiovascular and immune system regulation
3. An endogenous peptide responsible for widening blood vessels and enhancing capillary permeability, thereby inducing inflammation and nociception; it functions in diverse biological mechanisms including blood pressure control and immune reactions

Etymology: Bradykinin is a compound built from two Ancient Greek words: "bradús", meaning slow, and "kínēsis", meaning motion, with the chemical suffix "-in" attached. The name reflects what the substance was first observed to do. Researchers noticed a compound in blood that caused slow, sustained contraction of smooth muscle, such as the tissue lining the gut, and it was named for that effect. The "-in" ending is the standard suffix chemists use for proteins and peptides, so the name tells you it is a chemical compound rather than a physical process. Its job turned out to be the opposite of its name in one respect: rather than tightening vessels, bradykinin widens them, lowering blood pressure and making vessels more permeable. The name kept its original description of muscle action even after the broader role was understood.

Synonyms: peptide