(A) Survival after induction of PSA. (B) Hematocrit (HCT) determined 90 seconds after PSA induction. The change from baseline hematocrit, determined more than 7 days previously, is shown (mean ± SEM). (C) Survival after PAF injection (20 μg/kg i.v.). (D) Hematocrit measured 10 minutes after PAF injection. The change from baseline hematocrit, determined more than 7 days previously, is shown (mean ± SEM). (E and F) Mice were transfused with wild-type erythrocytes and studied 2 days later. (E) Survival of transfused mice after PAF injection (20 μg/kg i.v.). (F) Hematocrit determined 90 seconds after induction of PSA. The change from the hematocrit determined 2 hours previously is shown (mean ± SEM). Data were corrected for the drop in hematocrit caused by the blood draw at –2 hours. (G) Mice were injected with the S1pr1 agonist AUY954 (2 mg/kg i.v.) 2 minutes before PAF injection (20 μg/kg i.v.), and survival was followed. (H) Survival of pS1Pless mice and littermate controls after i.v. injection of histamine (200 mg/kg).