After its release and action, histamine is rapidly inactivated by enzymatic degradation. Two main enzymes are involved in histamine metabolism: histamine-N-methyltransferase (HNMT) and diamine oxidase (DAO). HNMT is primarily found in the brain and liver, while DAO is located in the gut, kidneys, and placenta. These enzymes convert histamine into inactive metabolites, preventing excessive accumulation and prolonged activity.
