The Chemiluminescence Response of Human Platelets

fractions were found to emit a burst of chemilumilinesceince during incubation with arachidonic acid. The magnitude of light emission was directly related to the number of platelets in the reaction mlixture and varied little for the same individual fromii day to day. The chemiiilunminescenice response of platelets vas localized to the particulate fraction aind was almiost totally oxygen dependent. In addition to arachidoniate, seven other polyunsaturated fatty acids, including several that are not prostaglandin precursors, also induced platelet chemiluminiescenice. A correlatioin was sought betweeni chemiiilumiiniescence and platelet prostaglandin synthesis. Platelets incub)ated in low concentrations of aspirini, or platelets from subjects who had ingested aspirini, had markedly decreased arachidonic acid-induced chemilumiinlesceiice. Salicylic and sulfosalicvlic acid had no inhibitory effect. A time-response curve of aspirin inhibition of arachidonate-induced chemiluminiescence closely paralleled a time-response curve of aspirin inhibition of malondialdehyde production. Linoleic acid-induced platelet chemiluminescence was also markedly inhibited using aspiriin-incubated platelets or platelets from subjects who had ingested aspirin. These studies implicate activation of the enzyme prostaglandin synthetase in the arachidonate-iinduced platelet chemiluminescence. They provide evidence that linoleic acid may also specifically activate platelet cyclooxygenase to produce electronically excited species capable of light emission