Biomaterial Database

Coronary vasospastic action of thromboxane A2 in isolated, working guinea pig hearts. 1978

Z I Terashita, and H Fukui, and K Nishikawa, and M Hirata, and S Kikuchi

The effects of thromboxane A2 (TXA2) on isolated, working guinea pig heart and left ventricular papillary muscle preparations were investigated. TXA2 was generated by the enzymatic conversion of prostaglandin H2 (PGH2) with indomethacin-treated horse platelet microsomes (IPM). TXA2 caused dose-dependently a considerable decrease in the coronary flow, left ventricular systolic pressure and left ventricular dp/dt in the perfused heart, while the similar effects of PGH2 were transient and weaker than those of TXA2. These effects of TXA2 disappeared after the TXA2-generating system was left standing at 37 degree C for 3 min. When IPM in the TXA2-generating system was pretreated with a TXA2 synthetase inhibitor, L-8027, the enhanced cardiac responses induced by the mixture of IPM and PGH2 disappeared. TXA2 had no direct effect on the contractile force of the papillary muscle. These results suggest that TXA2 has a specific coronary vasopastic action without a direct inotropic effect.

UI	MeSH Term	Description	Entries
D008297	Male		Males
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
D010210	Papillary Muscles	Conical muscular projections from the walls of the cardiac ventricles, attached to the cusps of the atrioventricular valves by the chordae tendineae.	Muscle, Papillary,Muscles, Papillary,Papillary Muscle
D011463	Prostaglandins H	A group of physiologically active prostaglandin endoperoxides. They are precursors in the biosynthesis of prostaglandins and thromboxanes. The most frequently encountered member of this group is the prostaglandin H2.
D003326	Coronary Circulation	The circulation of blood through the CORONARY VESSELS of the HEART.	Circulation, Coronary
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
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
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
D013928	Thromboxane A2	An unstable intermediate between the prostaglandin endoperoxides and thromboxane B2. The compound has a bicyclic oxaneoxetane structure. It is a potent inducer of platelet aggregation and causes vasoconstriction. It is the principal component of rabbit aorta contracting substance (RCS).	Rabbit Aorta Contracting Substance,A2, Thromboxane
D013930	Thromboxane-A Synthase	An enzyme found predominantly in platelet microsomes. It catalyzes the conversion of PGG(2) and PGH(2) (prostaglandin endoperoxides) to thromboxane A2. EC 5.3.99.5.	Thromboxane Synthetase,Thromboxane A Synthase,Thromboxane A2 Synthetase,A2 Synthetase, Thromboxane,Synthase, Thromboxane A,Synthase, Thromboxane-A,Synthetase, Thromboxane,Synthetase, Thromboxane A2