What is the antagonist of histamine?

Histamine antagonist is a medicine that binds to certain chemical histamine receptors and prevents the effects of this chemical in the body. Some of these drugs, also called antihistamines, reduce vasodilation responsible for common symptoms of allergy such as runny nose and swelling. The first drugs in this series also had wide effects on the nervous system, including sedation, but later were more specific. Another group of antagonists of histamine prevents stomach acid secretion and is used to treat digestion.

histamine is a modified form of amino acid histidine that increases the permeability of blood vessels to the cells of the immune system, allowing them to achieve infection and damage. Histamine antagonist is a chemical link to H1 or H2 receptors for histamine and blocks their effects on the body. When it binds to H1 respiratory receptors, histamine mediates nasal inflammation and breathing diffractive by allergies. Another class of histamine receptors, H2, starting the release of digestive acid in the acornto parietal cells.

Allergic reactions are hypersensitivity that triggers an immune cascade that releases histamine and mediates vasodilation. Histamine antagonist drugs called antihistamines are attached to H1 receptors located in respiratory epithelium. This prevents receptors in a way causing common symptoms of allergic response.

The nose and allergy -related eyes are the result of histamine induced by vasodilatation blocked by antihistamines. Sneezing is partially triggered by H1 receptors in the nose nerves and the antihistamine effect prevents their activation. While antagonists of histamine block the effect of chemicals, they do not prevent the body from being made.

Antihistamines of the first generation, such as Diphenhydramine, had sedative side effects, often caused drowsiness. Sometimes they are used in over -the -counter sleep aids and mild sedatives to use tohOto effect. These effects occurred because these drugs were not very selective for the H1 receptor and also bound to places with inhibitory effects on the nervous system, such as inducing sleepiness. Serotonin receptors were one of these places of antihistamine action. Second -generation antihistamines, such as Lorathidine, have been designed to be a more specific H1 histamine antagonist, limiting their side effects compared to earlier drugs.

gastroic acid is excreted by parietal stomach cells in response to chemical messengers including histamine. Excessive acid production is the cause of digestion or heartburn. The early class of antacid drugs acts as an antagonist of histamine, which competes with histamine to bind to H2 receptors and prevent parietal cells in the release of stomach acid. Cimetidine is an example of this H2 blockers have been used to treat digestive problems and sometimes to alleviate symptoms of peptic ulcers. Another class of drugs used to treat PThe heartburn, proton-pump inhibitors, proved to be more effective than histamine antagonist.