Source:http://linkedlifedata.com/resource/umls/id/C0034813
MSH: Cell-surface proteins that bind histamine and trigger intracellular changes influencing the behavior of cells. Histamine receptors are widespread in the central nervous system and in peripheral tissues. Three types have been recognized and designated H1, H2, and H3. They differ in pharmacology, distribution, and mode of action.,CSP: H1 receptors mediate smooth muscle contraction and are blocked by classic antihistamines; H2 mediate gastric acidification and certain smooth muscle functions and are blocked by cimetidine, burimamide, and related compounds.