Histamina, receptores y antagonistas

Antihistamines have been used for 50 years becoming one of the most prescribed drugs in Mexico. Current denomination is “Histamine Receptor Antagonists” and their main task is to avoid the afferent effect of histamine in many different body tissues. Histamine or β-aminoethylimidazole was isolated for the first time by Windaus and Vogt in 1907. In 1910 Daley and Laidlow studied its biological effect and found out that histamine stimulated diverse smooth muscles. In 1940 the first H1 antagonist antihistamine drug for use in human beings was developed: Antergan (fenobenzamine) with good results. In 1944 Neo-Antergan (Pyrilamine maleate) was commercialized in 1946, and further in 1946 diphenhydramine and tripelennamine and in 1949 clorpheniramine. All of these antihistamines was denominated as “First Generation”, “Classic”, or “Sedating”. In the last 15 years antihistamines with high inhibitory potential have been developed. Those are designated as “Second Generation” antihistamines. With the arrival of new research techniques, new histamine receptors were discovered: in 1966 H1 type, in 1972 H2 type, in 1983 H3 type and finally in 2000 H4 type. After releasing from mast cells, basophiles, histaminergic neurons or other any other cell type, histamine has to join to its receptor: H1, H2, H3 or H4 type. In the central nervous system H3 type is predominating, allowing self-regulated histamine production as neurotransmitter. Thus wakefulness along with as appetite, sleep and thermoregulation, are intensified by H1 type receptor. Today H4 type receptor is under study, and it is know that its function is regulated by inflammatory cytokine production, Therefore its participation in inflammatory processes is assumed. Conclusion: Actually a single pill is enough to block and control the pathologic effects of histamine, without undesirable secondary effects for the patient, giving him a normal quality of life.