Positive chronotropic effect of dialysable peptides derived from plasmin digestion of bovine fibrinogen preparations.
Low-molecular weight dialysable peptides, obtained by plasmin degradation of purified bovine fibrinogen preparations, have been shown to increase the chronotropic activity of isolated rat atria. This effect was dose dependent and was inhibited by inhibitors of glycolysis (NaF and 2-deoxy-D-glucose), but not by an inhibitor of oxidative phosphorylation (2, 4-dinitrophenol). Propranolol, a beta-blocking agent, was also ineffective. Fibrinogen-derived peptides increased both cAMP levels and phosphorylase alpha activity in stimulated atria. The increase of these parameters was transitory and appeared to precede the occurrence of the positive chronotropic effect. In the test situation used, the biochemical and functional modifications induced by fibrinogen-derived peptides were similar to those induced by glucagon.
D000818:Animals; D002417:Cattle; D000242:Cyclic AMP / Q000032:analysis; D003956:Dialysis; D005338:Fibrin Fibrinogen Degradation Products / Q000494:pharmacology*; D006325:Heart Atria / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects*; D066298:In Vitro Techniques; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects; D009206:Myocardium / Q000201:enzymology / Q000378:metabolism; D010455:Peptides / Q000302:isolation & purification / Q000494:pharmacology*; D006005:Phosphorylases / Q000032:analysis; D051381:Rats; D013268:Stimulation, Chemical; D013997:Time Factors
D005338:Fibrin Fibrinogen Degradation Products; D010455:Peptides; D000242:Cyclic AMP; D006005:Phosphorylases