An insect bite may result in inflammation of that spot. This is triggered by the alarm chemicals such as histamine and kinins. Histamine is a biogenic amine involved in local immune responses as well as regulating physiological function in the gut and acting as a neurotransmitter. It is found in virtually all animal body cells. New evidence also indicates that histamine plays an important role in chemotaxis of white blood cells. Kinin is any of various structurally related polypeptides, such as bradykinin and kallikrein. They are members of the autacoid family. They act locally to induce vasodilation and contraction of smooth muscles .