ROLE OF HISTAMINE AND ACETYLCHOLINE IN THE MECHANISM OF HEAT ALLERGY

Abstract

INSTANCES of heat allergy, while not common, are not new. Duke¹ in 1925 grouped all hypersensitivities to cold, heat, pressure and light under the term "physical allergy." He introduced the term to indicate an altered reactivity to physical agents. It has been proposed that physical agents release a histamine-like substance in the tissues and that this, in turn, produces subsequent allergic phenomena. However, it has become increasingly apparent that histamine alone is unable to account for all these phenomena. In recent years there have been a number of investigations which tend to show that the chemical substance that mediates allergy is acetylcholine. This belief has been fostered by the fact that some allergic manifestations can be produced by certain cholinergic drugs. For example, acetylcholine chloride in doses of 30 to 40 mg. will precipitate an attack of asthma in a susceptible patient. Encouraging results have been obtained from the