Histamine is a critical mediator of IgE/mast cell-mediated anaphylaxis. a neurotransmitter and a regulator of gastric acid secretion. Histamine is a monoamine synthesized from the amino acid histidine through a reaction catalyzed by the enzyme histidine decarboxylase (HDC). which removes carboxyl group from histidine. https://allfixelectricales.shop/product-category/telephone-extension-lead/