Histamine is a substance that is involved in numerous biological and physiological processes. It is synthesised and stored in granules inside certain blood cells (basophils and mast cells) that are part of the immune system and is also present in many foods either naturally or as a result of the action of micro-organisms.
At a physiological level, histamine participates in the stimulation of gastric juice secretion, inflammation, neurotransmission, smooth muscle contraction, haematopoiesis, vasodilation and cytokine production, among other processes.
When there is a deficit in the enzyme DAO at intestinal level, histamine is not eliminated correctly and is absorbed in the intestine through which when it reaches the blood it can accumulate in different tissues producing symptoms similar to an allergic reaction, such as headache, hives, diarrhoea and constipation.
It is known that there are certain polymorphisms in the AOC1 gene that can reduce the activity of the enzyme diamine oxidase or DAO. In addition, there is another enzyme known as HNMT that also plays a relevant role in histamine metabolism. In the intestine the action of DAO predominates and HNMT also participates, while in the brain HNMT is the main enzyme responsible for eliminating histamine at intracellular level.
GENE OR REGION STUDIED