Histamine receptors: an overview

Histamine is widely distributed throughout the body and has a broad range of pharmacologic effects. The advent of selective agonists and antagonists has allowed the identification and characterization of three types of histamine receptor. These same compounds have helped in our understanding of physiologic and pathologic roles for histamine. Clearly, histamine plays a central role in the physiologic control of gastric acid secretion, and this fact has led to the use of H2 antagonists such as cimetidine, and ranitidine is the therapy of acid-related diseases such as peptic ulcer. Histamine is also one of the prime mediators of a variety of allergic reactions, and H1 antagonists play a therapeutic role in this context. However, despite the widespread distribution of histamine receptors in, for example, the central nervous, respiratory, cardiovascular, and immune systems, other physiologic roles for histamine have not been established. It is to be hoped that future research will alter this situation and possibly lead to other therapeutic indications for histamine agonists and antagonists.