Effect of cations on the blood platelet release reaction.
1. Stimulus-secretion phenomena in blood platelets incubated with trypsin or thrombin have been investigated.2. Secretion occurs in at least two stages: (a) induction, obtained when the platelets are incubated with proteolytic enzymes in the presence of the chelating agent EDTA, and (b) release, which occurs with the subsequent addition of Ca(2+) to the incubation medium.3. Ca(2+) was the only essential divalent cation required for release. Ba(2+) and Mg(2+) inhibited release and Sr(2+) could only partially substitute for Ca(2+).4. Blood platelets exhibited recovery from enzymic perturbation by trypsin or thrombin by a mechanism that was temperature dependent, but did not require the synthesis of new protein.5. The results are discussed in relationship to stimulus-secretion in other cells.
D000227:Adenine Nucleotides / Q000378:metabolism; D000818:Animals; D001464:Barium / Q000494:pharmacology; D001792:Blood Platelets / Q000187:drug effects*; D002118:Calcium / Q000494:pharmacology; D002247:Carbon Isotopes; D002413:Cations, Divalent / Q000494:pharmacology*; D002462:Cell Membrane / Q000201:enzymology; D003470:Culture Media; D004492:Edetic Acid; D005260:Female; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D008274:Magnesium / Q000494:pharmacology; D011817:Rabbits; D012636:Secretory Rate / Q000187:drug effects; D012701:Serotonin / Q000378:metabolism; D013268:Stimulation, Chemical; D013324:Strontium / Q000494:pharmacology; D013696:Temperature; D013917:Thrombin / Q000494:pharmacology*; D014357:Trypsin / Q000494:pharmacology*; D014361:Trypsin Inhibitors / Q000494:pharmacology
D000227:Adenine Nucleotides; D002247:Carbon Isotopes; D002413:Cations, Divalent; D003470:Culture Media; D014361:Trypsin Inhibitors; D001464:Barium; D012701:Serotonin; D004492:Edetic Acid; D014357:Trypsin; D013917:Thrombin; D008274:Magnesium; D002118:Calcium; D013324:Strontium