title: Enhancement of cardiac performance of isolated working guinea pig heart by rabbit platelet and involvement of histamine.
abstract: Alterations of cardiac performance by washed rabbit platelets were investigated in isolated working guinea pig hearts. Enhanced cardiac functions emerged about 5 s after intracardiac injection of platelet suspension (6 x 10(8)-10 x 10(8) cells.ml-1). The LVP, +dP/dtmax, -dP/dtmax, and HR were increased by 30%, 73%, 46%, and 13% (P < 0.05 or 0.01), respectively, and recovered about 10 min later. In the range of 1 x 10(8)-70 x 10(8) cells.ml-1, platelet suspension strengthened the cardiac performance in a concentration-dependent manner. The supernatant demonstrated positive inotropic and chronotropic effects as well, quite similar to those of the suspension. Cimetidine (Cim, 1 mumol.L-1) reduced the cardiotonic effect of the platelet. Mast cell of the isolated guinea pig heart was proven to be in activated state upon 10(9) cells.ml-1 platelet challenge by electron microscopy. Histamine content in platelet suspension measured by HPLC was shown to be 2.6 +/- s 0.7 microgram per 10(9) platelets. It is concluded that histamine, released from platelets and cardiac mast cells, was a key factor in the cardiac alterations.
authors.affiliation: Research Section of Pharmacology, Hu-nan Medical University, Changsha, China.
authors.forename: Z G
authors.initials: ZG
authors.lastname: Guo
authors.forename: Y L
authors.initials: YL
authors.lastname: Chen
authors.forename: D N
authors.initials: DN
authors.lastname: Xie
mesh_terms: D000818:Animals; D001792:Blood Platelets / Q000378:metabolism / Q000502:physiology; D002927:Cimetidine / Q000494:pharmacology*; D006168:Guinea Pigs; D006339:Heart Rate; D006632:Histamine / Q000378:metabolism*; D066298:In Vitro Techniques; D008407:Mast Cells / Q000378:metabolism / Q000648:ultrastructure; D009200:Myocardial Contraction; D011738:Pyrilamine / Q000494:pharmacology; D011817:Rabbits
chemical_list: D002927:Cimetidine; D006632:Histamine; D011738:Pyrilamine