title: Preliminary evidence for two subclasses of histamine H2-receptors.
mesh_terms: D000403:Airway Resistance / Q000187:drug effects; D000818:Animals; D001980:Bronchi / Q000187:drug effects; D006632:Histamine / Q000494:pharmacology; D006801:Humans; D011968:Receptors, Histamine / Q000145:classification*; D011969:Receptors, Histamine H1 / Q000187:drug effects; D011970:Receptors, Histamine H2 / Q000145:classification* / Q000187:drug effects; D013045:Species Specificity; D014132:Trachea / Q000187:drug effects
chemical_list: D011968:Receptors, Histamine; D011969:Receptors, Histamine H1; D011970:Receptors, Histamine H2; D006632:Histamine