Histaminmediationsbaserat

Histaminmediationsbaserat refers to biological processes and responses that are mediated by histamine. Histamine is a biogenic amine produced from histidine and stored in granules of mast cells, basophils and certain neurons. It is released in response to allergens, tissue injury or other stimuli and acts on specific receptors to influence vascular, nervous and immune functions. The term captures the idea that histamine's effects arise from its signaling rather than from histamine alone.

Histamine acts through four G protein–coupled receptors: H1, H2, H3 and H4. Each receptor has distinct tissue distributions and signaling outcomes. H1 receptor activation promotes vasodilation, increased vascular permeability, bronchoconstriction and itch. H2 receptors regulate gastric acid secretion and participate in immune modulation. H3 receptors are largely presynaptic in the central nervous system and modulate the release of neurotransmitters. H4 receptors are expressed on various immune cells and influence chemotaxis, cytokine production and inflammatory responses.

Physiologically, histamine plays a role in defense against pathogens, wound healing, allergic reactions and maintaining gastric acidity. It also participates in certain aspects of neurotransmission and sleep–wake regulation. Clinically, dysregulation of histamine signaling can contribute to allergic diseases such as rhinitis, urticaria and anaphylaxis, and to gastrointestinal or cutaneous symptoms. Histamine intolerance may arise when metabolism or clearance is impaired, commonly due to reduced activity of enzymes such as diamine oxidase (DAO) or histamine-N-methyltransferase (HNMT).

Management of histamine-mediated conditions includes antihistamines (primarily H1 blockers), sometimes H2 blockers for gastric symptoms, mast cell stabilizers, and in certain cases targeted therapies. Ongoing research explores selective modulation of H3 and H4 receptors to treat inflammatory and neuropsychiatric conditions.