Developments in antihistamines (H1).

Abstract

Histamine (4(5)-imidazolylethylamine) is widely distributed in nature both in the plant and the animal kingdom. It was first chemically synthesized by Windaus and Vogt [1] in 1907 because of its structural similarity with the naturally occurring alkaloid pilocarpine and the amino acid histidine. This was followed by its preparation by bacterial decarboxylation of histidine [2] and its isolation from ergot [3, 4]. It was at this time that its physiological effects, particularly as a stimulant of smooth muscle contraction were first recognized [5–7]. Later histamine was isolated from various animal tissues, thus establishing that it is a natural constituent of the body [8, 9]. In mammalian brain it is found both in neurons and non-neuronal compartments like mast cells and capillary endothelial cells [10–18]. Recently, using immunohistological techniques [19–23], it has been shown that cell bodies immunoreactive to histamine and histidine decarboxylase are restricted to the ventral part of the posterior hypothalamus and mammillary nuclei regions but send projections to almost all regions of the diencephalon and telencephalon. It is because of such a wide distribution of histamine in the body that it can participate in a variety of physiological and pharmacological processes in different systems ranging from cardiovascular to gastrointestinal and neuroendocrine [24–44].KeywordsHistamine ReceptorQSAR StudyTrans ConformationGauche ConformationAntihistaminic ActivityThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.