Biomaterial Database

Irreversible blockade of responses to a partial agonist acting at the histamine H1-receptor. 1982

D Cook, and D Iwanow, and T Kenakin, and C Krueger

N,N-Diethyl-2-(1-pyridyl)-ethylamine (E-2-P) has been shown previously to behave as a simple partial agonist at the histamine H1-receptor of guinea-pig ileum. When isolated longitudinal muscle strips from this preparation were tested with E-2-P before and after blockade with 2-haloalkylamines, it was found that these agents produced an irreversible shift to the right in the dose-response curve without significant depression of the maximum response even at very high antagonist concentrations. Under these circumstances the maximum response to the partial agonist may exceed the maximum response to histamine itself since the latter shows a much diminished maximum response at a very high concentrations of antagonist. These findings are not readily explicable in terms the usual "receptor-reserve' model of the histamine receptor system in ileum. A tentative explanation is provided, involving interaction with the antagonist at more than one site.

UI	MeSH Term	Description	Entries
D009119	Muscle Contraction	A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.	Inotropism,Muscular Contraction,Contraction, Muscle,Contraction, Muscular,Contractions, Muscle,Contractions, Muscular,Inotropisms,Muscle Contractions,Muscular Contractions
D010643	Phenoxybenzamine	An alpha-adrenergic antagonist with long duration of action. It has been used to treat hypertension and as a peripheral vasodilator.	Dibenylene,Dibenyline,Dibenziran,Dibenzylin,Dibenzyline,Dibenzyran,Phenoxybenzamine Hydrochloride,Hydrochloride, Phenoxybenzamine
D011968	Receptors, Histamine	Cell-surface proteins that bind histamine and trigger intracellular changes influencing the behavior of cells. Histamine receptors are widespread in the central nervous system and in peripheral tissues. Three types have been recognized and designated H1, H2, and H3. They differ in pharmacology, distribution, and mode of action.	Histamine Binding Sites,Histamine Receptors,Histamine Receptor,Binding Sites, Histamine,Receptor, Histamine,Sites, Histamine Binding
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
D003983	Dibenzylchlorethamine	An alpha adrenergic antagonist.	Dibenamine,Dibenzyl Chlorethylamine,Chlorethylamine, Dibenzyl
D005021	Ethylamines	Derivatives of ethylamine (the structural formula CH3CH2NH2).
D006168	Guinea Pigs	A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.	Cavia,Cavia porcellus,Guinea Pig,Pig, Guinea,Pigs, Guinea
D006632	Histamine	An amine derived by enzymatic decarboxylation of HISTIDINE. It is a powerful stimulant of gastric secretion, a constrictor of bronchial smooth muscle, a vasodilator, and also a centrally acting neurotransmitter.	Ceplene,Histamine Dihydrochloride,Histamine Hydrochloride,Peremin
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D066298	In Vitro Techniques	Methods to study reactions or processes taking place in an artificial environment outside the living organism.	In Vitro Test,In Vitro Testing,In Vitro Tests,In Vitro as Topic,In Vitro,In Vitro Technique,In Vitro Testings,Technique, In Vitro,Techniques, In Vitro,Test, In Vitro,Testing, In Vitro,Testings, In Vitro,Tests, In Vitro,Vitro Testing, In