Histamine receptor

Source: Wikipedia, the free encyclopedia.

The histamine receptors are a class of

endogenous ligand.[1][2]

Histamine receptors are proteins that bind with histamine, a neurotransmitter involved in various physiological processes. There are four main types: H1, H2, H3, and H4. H1 receptors are linked to allergic responses, H2 to gastric acid regulation, H3 to neurotransmitter release modulation, and H4 to immune system function.

There are four known histamine receptors:

  • H1 receptor H1 Receptors: These receptors are primarily located on smooth muscle cells, endothelial cells, and neurons. Activation of H1 receptors mediates various responses, including smooth muscle contraction (leading to bronchoconstriction, intestinal cramping), increased vascular permeability (resulting in edema), and stimulation of sensory nerve endings (causing itching and pain). H1 antagonists, commonly known as antihistamines, are used to alleviate symptoms of allergies and allergic reactions. [3]
  • H2 receptor H2 Receptors: Found mainly in the stomach lining (parietal cells), H2 receptors regulate gastric acid secretion by stimulating the production of hydrochloric acid. H2 antagonists (H2 blockers) are used to reduce stomach acid production and treat conditions like gastroesophageal reflux disease (GERD) and peptic ulcers.[3]
  • H3 receptor H3 Receptors: These receptors are predominantly located in the central nervous system (CNS), particularly in regions associated with neurotransmitter release and modulation. H3 receptors act as presynaptic autoreceptors and heteroreceptors, regulating the release of neurotransmitters such as dopamine, serotonin, norepinephrine, and acetylcholine. Modulation of H3 receptors is being explored as a potential target for various neurological and psychiatric disorders.[4]
  • H4 receptor H4 Receptors: Initially discovered on immune cells, particularly mast cells, eosinophils, and T cells, H4 receptors are involved in immune responses, including chemotaxis (cellular movement in response to chemical signals) and cytokine production. These receptors play a role in inflammation and allergic reactions. Research on H4 receptors is ongoing to better understand their involvement in immune-related disorders and to develop potential therapeutic interventions.[5]

Comparison

Histamine receptors
Receptor Location Mechanism of action Function Antagonists Uses of antagonists
H1 Throughout the body, especially in:
endothelial cells (cells of walls of blood vessels)
  • adrenal medulla
  • heart
  • brain
  • spinal cord
    		•
    Gq
    • ileum contraction
    • modulate
      circadian cycle
    • itching
    • vasodilatation (indirect effect throughout the increased production of NO
      )
    • bronchoconstriction (allergy-induced asthma)
    H2
    Gs
    ↑ cAMP2+
    H3
    Gi
    H4
    Gi
    		 As of July 2021, no clinical uses exist.
    Potential uses include:
    pruritus

    There are several

    feedback inhibition
    of histamine.

    References

    1. PMID 9311023
      .
    2. S2CID 222842322
      .
    3. ^
      PMID 15548781
      .S
    4. S2CID 31148156
      .
    5. PMID 10973974
      .
    6. ^ "Histamine H1 Receptor - an overview | ScienceDirect Topics". www.sciencedirect.com. Retrieved 2023-10-03.
    7. PMID 25363289
      .
    8. S2CID 14932773
      .
    9. ^ "Histamine H4 Receptor Antagonist - an overview | ScienceDirect Topics". www.sciencedirect.com. Retrieved 2023-10-03.
    10. PMID 28446753
      .

    External links
    Retrieved from "https://en.wikipedia.org/w/index.php?title=Histamine_receptor&oldid=1199066070"