1907— Adolf Windaus and his associate W. Vogt produce histamine synthetically by removing the carboxyl group from the amino acid histidine.

1910—Henry Dale and his colleagues at the Wellcome Physiological Research Laboratories isolate histamine from mold and show that it can elicit the physiological responses associated with allergic reaction.

1927—Researchers discover histamine in vertebrate tissue, particularly in the lungs.

1942—Antergan becomes the first antihistamine tested in humans and goes on the market.

1972—James Black discovers the H2 receptor and characterizes its antagonist, burimamide.

1999—Researchers at a subsidiary of Johnson & Johnson clone the H3 receptor.

2000—Seven groups in the US, Europe and Japan clone the H4 receptor.

2006—Phase 1 clinical trials of H3 antagonists for neurological disorders begin.

2010—Spain's Palau Pharma announces favorable results from a phase 1 clinical study of its H4 antagonist for nasal allergies.