Biomaterial Database

Effect of platelet-activating factor (PAF) on sodium calcium exchange in cardiac sarcolemmal vesicles. 1990

H P Meng, and M J Kutryk, and G N Pierce

Division of Cardiovascular Sciences, St. Boniface General Hospital Research Center, Winnipeg, Canada.

The effects of platelet-activating factor (PAF) on Na(+)-dependent calcium uptake in myocardial sarcolemmal vesicles were examined in order to clarify its mechanism of inotropic action on the heart. PAF (40 and 20 microM) significantly inhibited Na(+)-Ca2+ exchange by 61% and 37%, respectively. Both initial rate of exchange and maximal exchange were inhibited. The Km for the reaction was not altered but Vmax was lowered 55% by PAF. Lyso-PAF inhibited Na(+)-Ca2+ exchange to a similar degree as PAF. CV-3988, a specific PAF receptor antagonist, failed to diminish the inhibitory effect of PAF on Na(+)-Ca2+ exchange, suggesting that the effect of PAF on Na(+)-Ca2+ exchange is not via a receptor mechanism. The passive permeability of sarcolemmal vesicles to Ca2+ was markedly elevated after PAF treatment. However, this effect could not account for the decrease in Na(+)-Ca2+ exchange. Interestingly, passive Ca2+ binding to cardiac sarcolemma was increased by 40 microM PAF. This study indicates that a depression of Na(+)-Ca2+ exchange probably does not play a role in the negative inotropic effect of PAF on the myocardium under physiological conditions. Its mechanism of action on Na(+)-Ca2+ exchange is discussed.

UI	MeSH Term	Description	Entries
D009206	Myocardium	The muscle tissue of the HEART. It is composed of striated, involuntary muscle cells (MYOCYTES, CARDIAC) connected to form the contractile pump to generate blood flow.	Muscle, Cardiac,Muscle, Heart,Cardiac Muscle,Myocardia,Cardiac Muscles,Heart Muscle,Heart Muscles,Muscles, Cardiac,Muscles, Heart
D010972	Platelet Activating Factor	A phospholipid derivative formed by PLATELETS; BASOPHILS; NEUTROPHILS; MONOCYTES; and MACROPHAGES. It is a potent platelet aggregating agent and inducer of systemic anaphylactic symptoms, including HYPOTENSION; THROMBOCYTOPENIA; NEUTROPENIA; and BRONCHOCONSTRICTION.	AGEPC,Acetyl Glyceryl Ether Phosphorylcholine,PAF-Acether,Phosphorylcholine, Acetyl Glyceryl Ether,1-Alkyl-2-acetyl-sn-glycerophosphocholine,Platelet Aggregating Factor,Platelet Aggregation Enhancing Factor,Platelet-Activating Substance,Thrombocyte Aggregating Activity,1 Alkyl 2 acetyl sn glycerophosphocholine,Aggregating Factor, Platelet,Factor, Platelet Activating,PAF Acether,Platelet Activating Substance
D002118	Calcium	A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.	Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D004285	Dogs	The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)	Canis familiaris,Dog
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
D001692	Biological Transport	The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.	Transport, Biological,Biologic Transport,Transport, Biologic
D012508	Sarcolemma	The excitable plasma membrane of a muscle cell. (Glick, Glossary of Biochemistry and Molecular Biology, 1990)	Sarcolemmas
D012964	Sodium	A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.	Sodium Ion Level,Sodium-23,Ion Level, Sodium,Level, Sodium Ion,Sodium 23