title: Effects of high pressure on platelet aggregation in vitro.
abstract: An apparatus which enables aggregating agents to be added to a stirred suspension of platelets subjected to a pressure of up to 600 ATA is described. The ensuing aggregation reaction is monitored optically. The pressure is applied with helium; data are presented that indicate the effects are mainly attributable to hydrostatic pressure. The aggregation of human platelets induced by ADP was reversibly inhibited by pressure in the 1-270 ATA range. The second phase of aggregation was blocked by 65 ATA; the rate of first phase aggregation was reduced but the time to respond to ADP was not affected. Comparable pressures also affected collagen and arachidonate-induced aggregation. The time to respond to these aggregating agents was prolonged and both the rate and the degree of aggregation were reduced by pressure.
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000494:pharmacology; D003094:Collagen / Q000494:pharmacology; D003664:Decompression; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006874:Hydrostatic Pressure; D010974:Platelet Aggregation / Q000187:drug effects; D011312:Pressure
chemical_list: D001095:Arachidonic Acids; D016718:Arachidonic Acid; D000244:Adenosine Diphosphate; D003094:Collagen