Histamine receptors
Histamine receptors are G-protein-coupled receptors through which the neurotransmitter and the tissue hormone histamine mediate their functions. To the family of histamine receptors include the receptors H 1 , H 2 , H 3 and H 4 . The receptors H 1 , H 2 and H 4 are particularly responsible for the effects of histamine in the context of defense reactions , such as mast cell activation , release of interleukins , recruitment of leukocytes , reddening of the skin, gastric acid release , vomiting and the expansion and increase of the permeability of small blood vessels associated with hives responsible. The H 3 receptor, in addition to the H 1 receptor, mediates the neurotransmitter functions of histamine. These include, for example, the regulation of the release of histamine (autoregulation), acetylcholine , noradrenaline and serotonin and the regulation of the circadian rhythm .
| H1 | H2 | H3 | H4 | |
|---|---|---|---|---|
| genetics | ||||
| Gene locus | 3q25 | 5q35 | 20q13.33 | 18q11.2 |
| Exons | 1 | 1 | 3 | 3 |
| protein | ||||
| structure | 7TM | 7TM | 7TM | 7TM |
| length | 487 amino acids | 359 amino acids | 445 amino acids | 390 amino acids |
| pharmacology | ||||
| Signal transduction | G q / 11 | G s | G i / o | G i / o |
| function | systemic vasodilation reddening of the skin day-night rhythm vomiting bronchoconstriction |
Gastric acid secretion reflex tachycardia |
Neurotransmission | Mast cell chemotaxis |
| Agonists | Histamine histaprodifen |
Histamine betazole |
Histamine α-methylhistamine Immepip Imetit |
Histamine 4-methylhistamine |
| Antagonists |
Loratadine Cetirizine Fexofenadine Doxylamine Diphenhydramine |
Cimetidine famotidine ranitidine roxatidine |
Ciproxifan Thioperamide Clobenpropit |
Thioperamide JNJ 7777120 |
literature
- CR Ganellin: Pharmacology of Histamine Receptors. Elsevier, 2013, ISBN 978-1-483-19341-0 .