Low-density lipoproteins increase intracellular calcium in aequorin-loaded platelets.
Low-density lipoproteins activate isolated human platelets. The mechanism of this activation is unknown, but may involve increased phosphoinositide turnover. We have examined the effect of low-density lipoproteins on intracellular calcium concentrations in platelets loaded with the photoprotein aequorin. The lipoproteins induced concentration-dependent increases in intracellular calcium, associated with shape change and aggregation. These responses could be partially inhibited by the removal of extracellular calcium and by pre-incubation with acetylsalicylic acid. They were also antagonised by agents which increase cellular concentrations of cyclic adenosine and guanosine monophosphates. It is not clear whether the platelet-lipoprotein interaction involves a 'classical' lipoprotein receptor.
Dunn
R C
RC
Department of Biochemistry, Royal Free Hospital School of Medicine, London, England.
Schachter
M
M
Miles
C M
CM
Feher
M D
MD
Tranter
P R
PR
Bruckdorfer
K R
KR
Sever
P S
PS
D000331:Aequorin; D001241:Aspirin / Q000494:pharmacology; D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism*; D002118:Calcium / Q000097:blood*; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000494:pharmacology; D006801:Humans; D007546:Isoquinolines / Q000494:pharmacology; D008077:Lipoproteins, LDL / Q000494:pharmacology*; D049449:Luminescence; D008164:Luminescent Proteins; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors; D044005:Tetrahydroisoquinolines
D007546:Isoquinolines; D008077:Lipoproteins, LDL; D008164:Luminescent Proteins; D010975:Platelet Aggregation Inhibitors; D044005:Tetrahydroisoquinolines; C016276:8-bromocyclic GMP; D000331:Aequorin; C035964:trequinsin; D006152:Cyclic GMP; D001241:Aspirin; D002118:Calcium