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 and Thyroid Health. Histamine is a chemical which plays a role in the inflammatory process, and also acts as a neurotransmitter. It is produced by certain white blood cells, specifically basophils and mast cells, although a few other cells can produce it as well, such as platelets and microglial cells.