Biomaterial Database

Theoretical studies on the histamine H2 receptor: molecular mechanism of action of antagonists. 1992

J Giraldo, and M Martín, and M Campillo, and L Pardo

Department of Biostatistics, Faculty of Medicine, Universidad Autónoma de Barcelona, Spain.

The previously defined sites in the histamine H2 receptor model [Mol. Pharmacol. 40:980-987 (1991)] were used to elucidate the pharmacological mechanism of action of compounds that act as antagonists at the receptor. In this model, a formate anion is used both as the negative site at which the histamine cation is anchored to the receptor and as a proton acceptor site. An ammonium cation is used as a proton donor site. The proposed model of recognition of cimetidine, tiotidine, and ranitidine suggests that the monocationic form of the antagonists is the most favorable species to bind the receptor. Moreover, the mode of recognition follows the same trends obtained for compounds that act as agonists; the protonated site of the molecule, i.e., imidazolium in cimetidine, guanidinium in tiotidine, or substituted ammonium in ranitidine, anchors at the negative site of the receptor, whereas the nonbasic part, i.e., cyanoguanidine in cimetidine and tiotidine and nitrodiaminoethene in ranitidine, is located between the proton donor and acceptor sites. An energetic analysis of the interaction between the antagonists and the receptor model, including the energies of ligand desolvation, shows that histamine cannot compete effectively with cimetidine, tiotidine, or ranitidine for binding to the H2 receptor. The predicted order of antagonist potencies, based on differences of formation enthalpies (delta delta H1), reproduces qualitatively the experimental rank order.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008956	Models, Chemical	Theoretical representations that simulate the behavior or activity of chemical processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.	Chemical Models,Chemical Model,Model, Chemical
D008968	Molecular Conformation	The characteristic three-dimensional shape of a molecule.	Molecular Configuration,3D Molecular Structure,Configuration, Molecular,Molecular Structure, Three Dimensional,Three Dimensional Molecular Structure,3D Molecular Structures,Configurations, Molecular,Conformation, Molecular,Conformations, Molecular,Molecular Configurations,Molecular Conformations,Molecular Structure, 3D,Molecular Structures, 3D,Structure, 3D Molecular,Structures, 3D Molecular
D011899	Ranitidine	A non-imidazole blocker of those histamine receptors that mediate gastric secretion (H2 receptors). It is used to treat gastrointestinal ulcers.	AH-19065,Biotidin,N (2-(((5-((Dimethylamino)methyl)-2-furanyl)methyl)thio)ethyl)-N'-methyl-2-nitro-1,1-ethenediamine,Ranisen,Ranitidin,Ranitidine Hydrochloride,Sostril,Zantac,Zantic,AH 19065,AH19065,Hydrochloride, Ranitidine
D011969	Receptors, Histamine H1	A class of histamine receptors discriminated by their pharmacology and mode of action. Most histamine H1 receptors operate through the inositol phosphate/diacylglycerol second messenger system. Among the many responses mediated by these receptors are smooth muscle contraction, increased vascular permeability, hormone release, and cerebral glyconeogenesis. (From Biochem Soc Trans 1992 Feb;20(1):122-5)	H1 Receptor,Histamine H1 Receptors,H1 Receptors,Histamine H1 Receptor,Receptors, H1,H1 Receptor, Histamine,H1 Receptors, Histamine,Receptor, H1,Receptor, Histamine H1
D002927	Cimetidine	A histamine congener, it competitively inhibits HISTAMINE binding to HISTAMINE H2 RECEPTORS. Cimetidine has a range of pharmacological actions. It inhibits GASTRIC ACID secretion, as well as PEPSIN and GASTRIN output.	Altramet,Biomet,Biomet400,Cimetidine HCl,Cimetidine Hydrochloride,Eureceptor,Histodil,N-Cyano-N'-methyl-N''-(2-(((5-methyl-1H-imidazol-4-yl)methyl)thio)ethyl)guanidine,SK&F-92334,SKF-92334,Tagamet,HCl, Cimetidine,Hydrochloride, Cimetidine,SK&F 92334,SK&F92334,SKF 92334,SKF92334
D003198	Computer Simulation	Computer-based representation of physical systems and phenomena such as chemical processes.	Computational Modeling,Computational Modelling,Computer Models,In silico Modeling,In silico Models,In silico Simulation,Models, Computer,Computerized Models,Computer Model,Computer Simulations,Computerized Model,In silico Model,Model, Computer,Model, Computerized,Model, In silico,Modeling, Computational,Modeling, In silico,Modelling, Computational,Simulation, Computer,Simulation, In silico,Simulations, Computer
D006146	Guanidines	A family of iminourea derivatives. The parent compound has been isolated from mushrooms, corn germ, rice hulls, mussels, earthworms, and turnip juice. Derivatives may have antiviral and antifungal properties.
D006634	Histamine H1 Antagonists	Drugs that selectively bind to but do not activate histamine H1 receptors, thereby blocking the actions of endogenous histamine. Included here are the classical antihistaminics that antagonize or prevent the action of histamine mainly in immediate hypersensitivity. They act in the bronchi, capillaries, and some other smooth muscles, and are used to prevent or allay motion sickness, seasonal rhinitis, and allergic dermatitis and to induce somnolence. The effects of blocking central nervous system H1 receptors are not as well understood.	Antihistamines, Classical,Antihistaminics, Classical,Antihistaminics, H1,Histamine H1 Antagonist,Histamine H1 Receptor Antagonist,Histamine H1 Receptor Antagonists,Histamine H1 Receptor Blockaders,Antagonists, Histamine H1,Antagonists, Histamine H1 Receptor,Antihistamines, Sedating,Blockaders, Histamine H1 Receptor,First Generation H1 Antagonists,H1 Receptor Blockaders,Histamine H1 Blockers,Receptor Blockaders, H1,Antagonist, Histamine H1,Classical Antihistamines,Classical Antihistaminics,H1 Antagonist, Histamine,H1 Antagonists, Histamine,H1 Antihistaminics,Sedating Antihistamines
D006635	Histamine H2 Antagonists	Drugs that selectively bind to but do not activate histamine H2 receptors, thereby blocking the actions of histamine. Their clinically most important action is the inhibition of acid secretion in the treatment of gastrointestinal ulcers. Smooth muscle may also be affected. Some drugs in this class have strong effects in the central nervous system, but these actions are not well understood.	Antihistaminics, H2,H2 Receptor Blockader,Histamine H2 Antagonist,Histamine H2 Blocker,Histamine H2 Receptor Antagonist,Histamine H2 Receptor Antagonists,Histamine H2 Receptor Blockader,Histamine H2 Receptor Blockaders,Antagonists, Histamine H2,Blockaders, Histamine H2 Receptor,H2 Receptor Blockaders,Histamine H2 Blockers,Receptor Antagonists, Histamine H2,Receptor Blockaders, H2,Antagonist, Histamine H2,Blockader, H2 Receptor,Blockaders, H2 Receptor,Blocker, Histamine H2,Blockers, Histamine H2,H2 Antagonist, Histamine,H2 Antagonists, Histamine,H2 Antihistaminics,H2 Blocker, Histamine,H2 Blockers, Histamine,Receptor Blockader, H2