Joe Hing Kwok Chu
Histamine is formed by decarboxylation of histidine. It is a potent hormone/chemical transmitter. It is a biogenic monoamine, like serotonone, epinephrine (adrenalin), norepinephrine (noradrenalin), involved in local immune responses, regulating stomach acid production and in allergic reactions. Antigen releases it from the mast cells. It causes the expansion of blood vessels, constricting smooth muscles (like stomach, intestines, bronchi, esophagus, bladder, and urethra).
It is responsible for the early symptoms of hypersensitive reaction to substances like animal protein, pollutions or chemicals.
It is also present in some venoms.
e jiao (donkey hide glue)
Pixu and Sugar