ABSTRACT
Histamine, an ubiquitous cell-to-cell messenger, was identified in 1910 by Dale and Laidlaw (1) and has been recognized since the 1920s as a major mediator of allergic disorders such as rhinitis, asthma, urticaria, and anaphylaxis. The precise mechanism of action of histamine remained unknown until 1966, when the H1histamine receptor was identified (2). Knowledge about the histaminergic system evolved with the subsequent discovery of the H2-receptor (3), involved in gastric acid secretion, and the H3-receptor (4) represented most prominently in the central nervous system (CNS) in humans.
