Light scattering changes of edetic acid-treated, washed rat platelets: effect of adenosine diphosphate and calcium ion in relation to chilling.
The effe-ts of adenosine diphosphate (ADP) and Ca2+ on platelet morphology were studied in edetic acid (EDTA)-treated, washed platelets of rat by means of light scattering measurement at right angles. ADP caused a transient change of light scattering, which was independent of concentration above 5 muM and of pH between 4 and 10. When the platelets were pretreated with ADP or chilled persistently, Ca2+ also caused another transient change of light scattering. The effect of Ca2+ was abolsihed at pH below 6.5. The velocity of both ADP- and Ca2+-induced response was dependnet on temperature, and the magnitude was reduced by metabolic inhibitors and SH-blocking agents. Adenosine triphosphate (ATP) competitively inhibited the ADP-induced response, but not the Ca2+-induced one. The response to Ca2+ of the control and chilled platelets was compared by scanning electron microgram. Apparent similarity of the effect of chilling on membrane structure to that of ADP was suggested.
D000244:Adenosine Diphosphate / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D001792:Blood Platelets / Q000187:drug effects* / Q000201:enzymology / Q000648:ultrastructure; D002118:Calcium / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D003080:Cold Temperature; D004492:Edetic Acid / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D008027:Light; D008274:Magnesium / Q000494:pharmacology; D008297:Male; D008855:Microscopy, Electron, Scanning; D051381:Rats; D013696:Temperature
D004791:Enzyme Inhibitors; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D004492:Edetic Acid; D000251:Adenosine Triphosphatases; D008274:Magnesium; D002118:Calcium