Biomaterial Database

Interaction between histamine and clonidine in isolated guinea-pig atria. 1982

E Rubio, and J Esplugues, and F J Morales-Olivas, and E Morcillo

1. This study investigates the chronotropic and inotropic effects of clonidine and its interaction with histamine in spontaneously beating and electrically driven isolated guinea-pig atria. 2. Clonidine (up to 100 microM) did not modify the force of contraction in either spontaneously beating or paced atria. 3. Clonidine increased the rate of beating, having a lower maximal effect (43 +/- 5%) and a higher EC50 (15.7 +/- 4 microM) than histamine (Emax = 100%; EC50 = 1.47 +/- 0.1 microM). 4. The positive chronotropic effect of clonidine was unchanged after clemizole, phentolamine, propranolol and atropine but was competitively antagonized by cimetidine (pA2 = 6.87 +/- 0.18). 5. Concentration-response curves for clonidine in the presence of several concentrations of histamine, and for histamine in the presence of several concentrations of clonidine, were constructed and the displacements observed with respect to the control curves in each case fit the competitive dualism model. 6. These results demonstrate that clonidine behaves as a partial agonist of the histamine H2-receptor in isolated guinea-pig atria.

UI	MeSH Term	Description	Entries
D009200	Myocardial Contraction	Contractile activity of the MYOCARDIUM.	Heart Contractility,Inotropism, Cardiac,Cardiac Inotropism,Cardiac Inotropisms,Contractilities, Heart,Contractility, Heart,Contraction, Myocardial,Contractions, Myocardial,Heart Contractilities,Inotropisms, Cardiac,Myocardial Contractions
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
D003000	Clonidine	An imidazoline sympatholytic agent that stimulates ALPHA-2 ADRENERGIC RECEPTORS and central IMIDAZOLINE RECEPTORS. It is commonly used in the management of HYPERTENSION.	Catapres,Catapresan,Catapressan,Chlophazolin,Clofelin,Clofenil,Clonidine Dihydrochloride,Clonidine Hydrochloride,Clonidine Monohydrobromide,Clonidine Monohydrochloride,Clopheline,Dixarit,Gemiton,Hemiton,Isoglaucon,Klofelin,Klofenil,M-5041T,ST-155,Dihydrochloride, Clonidine,Hydrochloride, Clonidine,M 5041T,M5041T,Monohydrobromide, Clonidine,Monohydrochloride, Clonidine,ST 155,ST155
D004347	Drug Interactions	The action of a drug that may affect the activity, metabolism, or toxicity of another drug.	Drug Interaction,Interaction, Drug,Interactions, Drug
D004558	Electric Stimulation	Use of electric potential or currents to elicit biological responses.	Stimulation, Electric,Electrical Stimulation,Electric Stimulations,Electrical Stimulations,Stimulation, Electrical,Stimulations, Electric,Stimulations, Electrical
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
D006321	Heart	The hollow, muscular organ that maintains the circulation of the blood.	Hearts
D006339	Heart Rate	The number of times the HEART VENTRICLES contract per unit of time, usually per minute.	Cardiac Rate,Chronotropism, Cardiac,Heart Rate Control,Heartbeat,Pulse Rate,Cardiac Chronotropy,Cardiac Chronotropism,Cardiac Rates,Chronotropy, Cardiac,Control, Heart Rate,Heart Rates,Heartbeats,Pulse Rates,Rate Control, Heart,Rate, Cardiac,Rate, Heart,Rate, Pulse
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