Definition of histamine

Histamine is an active amine compound that acts as a chemical substance in the body that can affect many cellular responses, including allergies, inflammatory reactions, gastric acid secretion, etc., and can also affect brain conduction Want to sleep and other effects.

Overview of histamine

Histamine is a biological amine that is widely present in plants and animals and is formed by decarboxylation of histidine, which is usually stored in tissue mast cells. In vivo, histamine is an important chemical neurotransmitter, when the body by some kind of stimulation caused by antigen-antibody reaction, causing mast cell cell membrane permeability changes, the release of histamine, and histamine receptor pathology Physiological effect.

Histamine synthesis process occurs mainly in mast cells, basophils, lungs, skin and gastrointestinal mucosa, and stored histamine tissue consistent.

In mast cells, histamine is stored as an inactive complex in the granule, which consists of histamine and polysulfide anions, heparin and an anionic protein. If not stored, will soon be inactivated by amine oxidase.

(Nπ-H-histamine, Nτ-H-histamine) is a biologically amines widely found in plants and animals.

Histamine history

The hay fever is very clear that pollen makes them sneeze, tears and runny nose. The earliest case of hay fever was recorded by Leonardo Botaro in 1565. He called it "rose hot".

In 1903, a German doctor named William Dunbar proved that this stimulated reaction was not caused by the pollen itself, but by the body's response to pollen caused by the release of a toxin caused. He worked hard to develop an antibiotic, but it did not work. Later, in his study of the toxicity of rye in 1910, Henry Dell discovered a substance he called "histamine". Until about 16 years later, he realized that histamine caused an allergic reaction. Since then, he has also found that damaged cells will produce their own histamine.

It was not until the 1950s that Daniel Eve of the Pasteur Institute in Paris developed antihistamines.

Asthma and eczema are also allergic reactions, but unfortunately antihistamines have no therapeutic effect on them. The body will always respond to the invasion of pollen and other stimuli. The problem with people with allergies is that they are too sensitive to a stimulus.

Histamine properties

Histamine is a self active substance widely found in human tissues. Histamine in tissues is mainly contained in mast cells and basophils. Therefore, containing more mast cells in the skin, bronchial mucosa and intestinal mucosal concentrations of histamine higher, cerebrospinal fluid also has a higher concentration. Histamine in mast cell granules often binds to proteins, and physical or chemical stimuli can degrade mast cells, leading to histamine release. Histamine binds to specific receptors on the target cells, producing biological effects; such as small arteries, small veins and capillaries, resulting in decreased blood pressure or even shock; increased heart rate and myocardial contractility, inhibition of atrioventricular conduction; excitatory smooth muscle, causing bronchial spasm , Gastrointestinal colic; stimulate the parietal cells, causing gastric acid secretion. Histamine receptors have H1, H2, H3 subtypes. The clinical application of histamine has been gradually reduced, but its receptor blockers are clinically significant.

Histamine function

Histamine is present in mast cells and is present in the mucosal tissues of the lung, liver and stomach. It plays a very important role in the regulation of allergies and inflammation. Histamine belongs to a chemical message, is also the amine neurotransmitter, involved in the central and peripheral multiple physiological functions. In the central system, histamine is synthesized by specific nerves, such as nodules in the posterior part of the hypothalamus - the nucleus of the nipple, the nerve cells extending extensively to the rest of the brain and the spine, suggesting that histamine may be involved in sleep, hormonal secretion, Body temperature regulation, appetite and memory formation and other functions, in addition to the network structure and end of the brain; in the peripheral part of the main histamine stored in mast cells, basophils and intestinal chromaffin cells can cause itching, sneezing, Nasal water and other phenomena, in addition to the combination of histamine on the vascular smooth muscle receptors (H1R) lead to vasodilation and thus produce local edema, histamine will make lung tracheal smooth muscle contraction caused by respiratory stenosis and difficulty breathing, intestinal smooth muscle contraction lower blood pressure and increase Heartbeat (tachycardia) and many other physiological reactions.

Histamine poisoning and clinical manifestations

Drug poisoning: histamine is mainly used for gastric secretion test, for the maximum acid secretion (MAO) determination. But has been replaced by pentapeptide gastrin. Histamine by activating the body histamine H1 receptor and H2 receptor, contraction of a variety of smooth muscle such as trachea, bronchial and gastrointestinal smooth muscle; but at the same time relaxation of small blood vessels smooth muscle, increased capillary permeability; also strongly stimulate gastric acid secretion, Slow down atrioventricular conduction, increase myocardial contractility and so on. Misuse of large doses or intravenous administration can cause poisoning. Injection over 1 to 5 minutes after the emergence of skin flushing, dizziness, headache, nausea, tachycardia, various types of arrhythmia and hypotension and other reactions. And can occur urticaria, asthma-like seizures, laryngeal spasm and vascular edema and so on. Can also cause stress ulcers and gastrointestinal bleeding. Occasional persistent hypotension, difficulty breathing and other serious consequences.

Food poisoning: a large number of tests show that seafood fish in the red skin of fish with high histamine, when the fish is not fresh or corrupt, the fish in the free histidine by decarboxylase production histamine histamine poisoning latency Usually for 0.5 to 1 hour, the shortest can be 5min, up to 4h. After food poisoning, local or systemic capillary expansion, increased permeability, bronchial contraction, the main symptoms of blush, dizziness, headache, palpitation, pulse , Chest tightness and respiratory distress, and some patients with conjunctival hyperemia, pupil scattered, blurred vision, face up, lip edema, mouth and tongue and limbs numbness, nausea, vomiting, diarrhea, measles, flushing, blood pressure.

Detection of histamine

A large number of food easy to residual histamine drugs, the human body has some harm. At present, for the general government quality inspection agencies, veterinary drug monitoring, commodity inspection bureau, and food enterprises: agricultural and livestock products processing and export enterprises, aquatic enterprises, honey enterprises and other public grass-roots laboratories, the most is the enzyme application of immunosorbent assay kit, Ie ELISA method.

Compared with the detection method, the ELISA method has the advantages of high sensitivity, low detection cost, fast and convenient, simultaneous high-volume screening and simple operation.