Summary: (from NCBI-Entrez) Histamine is a ubiquitous messenger molecule released from mast cells, enterochromaffin-like cells, and neurons. Its various actions are mediated by histamine receptors H1, H2, H3 and H4. This gene was thought to be intronless until recently. The protein encoded by this gene is an integral membrane
..[read more]Histamine is a ubiquitous messenger molecule released from mast cells, enterochromaffin-like cells, and neurons. Its various actions are mediated by histamine receptors H1, H2, H3 and H4. This gene was thought to be intronless until recently. The protein encoded by this gene is an integral membrane protein and belongs to the family 1 of G protein-coupled receptors. It mediates the contraction of smooth muscles, increase in capillary permeability due to contraction of terminal venules, catecholamine release from adrenal medulla, and mediates neurotransmission in the central nervous system.