Significance of myocardial prostaglandin biosynthesis and the influence of mechanical loading, endogenous mediators and cardiovascular drugs.
Isolated perfused and electrically driven heart preparations of guinea pigs and tissue from different parts of the rabbit hearts have the capacity to rapidly synthesize prostacyclin (PGI2) and thromboxane (TXB2). Auricles showed a higher PGI2 formation than ventricles. Addition of arachidonic acid or PGH2 markedly enhanced the myocardial PGI2 biosynthesis. After acute pressure overload by a graduated aortic stenosis the PGI2 and TXB2 formation of the myocardium is decreased possibly caused by a diminished availability of substrate, an alteration of enzyme activities or changes in the functional state of the cardiac tissue. Pretreatment with dipyridamole or propranolol again induced an increase of this diminished PGI2 and TXB2 synthesis. The PGI2 formation of electrically driven ventricular strips enhanced with an increased stimulation rate. Ouabain, antianginal drugs (dipyridamole, oxyfedrine, propranolol) and endogenous mediators (norepinephrine, histamine, adenosine) induced a significant rise of the cardiac PGI2 formation. The results suggest that the cardiac prostaglandin biosynthesis is involved in the action of the myocardium indicating heart sufficiency and an adaptability to mechanical loading or drug influence.
D015121:6-Ketoprostaglandin F1 alpha / Q000096:biosynthesis; D000818:Animals; D015237:Dinoprost; D004176:Dipyridamole / Q000494:pharmacology*; D011464:Epoprostenol / Q000096:biosynthesis; D006321:Heart / Q000187:drug effects / Q000502:physiology*; D006325:Heart Atria / Q000378:metabolism; D006352:Heart Ventricles / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism; D011433:Propranolol / Q000494:pharmacology*; D011453:Prostaglandins / Q000096:biosynthesis*; D011458:Prostaglandins E / Q000096:biosynthesis; D011460:Prostaglandins F / Q000096:biosynthesis; D011817:Rabbits; D013929:Thromboxane B2 / Q000096:biosynthesis
D011453:Prostaglandins; D011458:Prostaglandins E; D011460:Prostaglandins F; D013929:Thromboxane B2; D015121:6-Ketoprostaglandin F1 alpha; D004176:Dipyridamole; D011433:Propranolol; D015237:Dinoprost; D011464:Epoprostenol