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Goodman & Gilman's The Pharmacological Basis of Therapeutics, 11e
| IV. Autacoids: Drug Therapy of Inflammation > |
Chapter 24. Histamine, Bradykinin, and Their Antagonists
Sections: Histamine, H1 Receptor Antagonists, The Histamine H3 Receptor and Its Ligands, The Histamine H4 Receptor and Its Ligands, Clinical Summary of Histamine Receptors and Their Ligands, Bradykinin, Kallidin, and Their Antagonists, Clinical Summary, Acknowledgment, Bibliography.
Topics Discussed: bradykinin; histamine; histamine antagonists.
Excerpt:
" The history of histamine ( -aminoethylimidazole)
parallels that of acetylcholine (ACh). Both compounds were synthesized as
chemical curiosities before their biological significance was recognized;
they were first detected as uterine stimulants in extracts of ergot,
from which they were subsequently isolated, and proved to be contaminants
of ergot derived from bacterial action.Histamine is a hydrophilic molecule consisting of an
imidazole ring and an amino group connected by two methylene groups.
The pharmacologically active form at all histamine receptors is the
monocationic N —H tautomer, i.e., the charged form of the species
depicted in Figure 24–1, although
different chemical properties of this monocation may be involved
in interactions with the H1 and H2 receptors (Ganellin and Parsons, 1982). The four classes
of histamine receptors can be activated differently by analogs of
histamine (Figure 24–1 and Table 24–1). Thus 2-methylhistamine
preferentially elicits responses mediated by H1 receptors,
whereas 4(5)-methylhistamine has a preferential..."
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