of, relating to, or of the nature of preference: preferential policies. 2. showing or giving preference: a preferential hiring system. 3. receiving or enjoying preference, as a country in trade relations; favored. Origin of preferential.
Histamine dilates post-capillary venules, activates the endothelium, and increases blood vessel permeability. This leads to local edema (swelling), warmth, redness, and the attraction of other inflammatory cells to the site of release. It also depolarizes nerve endings (leading to itching or pain).
histamine (hisÂ´tÉmÄnÂ´), n a compound found in all cells that is produced by the breakdown of histidine. It is released in allergic, inflammatory reactions and causes dilation of capillaries, decreased blood pressure, increased secretion of gastric juice, and constriction of smooth muscles of the bronchi and uterus.