The role of 1‐O‐alkyl‐2‐acetyl‐sn‐glyceryl‐3‐phosphorylcholine (AcGEPC) and palmitoyl‐lysophosphatidate in the responses of human blood platelets to collagen and thrombin

Desensitisation of human blood platelets to the effects of 1-O-alkyl-2-acetyl-sn-glyceryl-3-phosphorylcholine (1-O-alkylAcGEPC) and palmityl-lysophosphatidate by pre-incubation with these agonists has no effect on the aggregatory or secretory responses to collagen but causes 30-40% inhibition of these responses to thrombin in aspirin-treated platelets. The effects of 1-O-alkylAcGEPC and palmitoyl-lysophosphatidate are not additive. The results are not consistent with the proposal that 1-O-alkylAcGEPC or lysophosphatidate are the mediators for the responses to collagen observed when prostaglandinendoperoxide synthesis is prevented, although they may play some role in the responses to thrombin under these conditions.