AIM: To investigate the dynamic changes and significance of platelet activating factor receptor (PAF-R)mRNA and protein in pancreatic tissues of rats with severe acute pancreatitis (SAP) and effects of BN52021(Ginkgolide B).METHODS: Wistar male rats were randomly assigned to the negative control group (NC group), SAP model group (SAP group), and BN52051-remedy group (BN group), and each of the groups was divided into 6 subgroups at different time points after operation (1 h,2 h, 3 h, 6 h, 12 h, and 24 h) (n = 10 in each). PT-PCR and West blot methods were used to detect PAFRmRNA and protein expression in pancreatic tissues of rats respectively. Pathological examination of pancreatic tissues was performed and the serum amylase change was detected.RESULTS: Serum amylase and pathological results showed the that SAP model was successfully prepared,BN52021 was able to decrease serum amylase, and the pathological ratings in BN group at 3 h, 6 h, and 12 h significantly decreased compared with those in the SAP group (8.85 ± 0.39 vs 5.95 ± 0.19, 9.15 ± 0.55 vs 5.55 ± 0.36, 10.10 ± 0.65 vs 6.72 ± 0.30, P ＜ 0.05). The result of PAF-mRNA showed dynamic changes in SAP and BN groups, which increased gradually in early stage,reached a peak at 3 h (0.71 ± 0.14 vs 0.54 ± 0.14,0.69 ± 0.13 vs 0.59 ± 0.04, P ＜ 0.05), and decreased gradually later. There were significant differences at each time point except 1 h and 2 h, when compared with those in the NC group (0.71 ± 0.14 or 0.69 ± 0.13 vs 0.47 ± 0.10, 0.38 ± 0.08 or 0.59 ± 0.04 vs 0.47 ± 0.09, 0.25 ± 0.07 or 0.29 ± 0.05 vs 0.46 ± 0.10, 0.20 ± 0.06 or 0.20 ± 0.04 vs 0.43 ± 0.09, P ＜ 0.05), whereas there was no significant difference between BN and SAP groups at each time point. The result of PAF-R protein showed that the change of PAF-R protein in the SAP group and the BN group was consistent with that of PAF-R mRNA.There were significant differences at each time point except 1 h, when compared with those in the NC group (0.90 ± 0.02 or 0.80 ± 0.05 vs 0.48 ± 0.02, 1.69 ± 0.06 or 1.58 ± 0.02 vs 0.48 ± 0.03, 1.12 ± 0.10 or 0.98 ± 0.03 vs 0.49 ± 0.09, 1.04 ± 0.14 or 0.87 ± 0.02 vs 0.52 ± 0.08,0.97 ± 0.16 or 0.90 ± 0.05 vs 0.49 ± 0.10, P ＜ 0.05),whereas there was no significant difference between the BN group and the SAP group.CONCLUSION: PAF-R plays an important role in occurrence and development of SAP. BN52021 exerts biological effects through competitively inhibiting the binding of increased both PAF and PAF-R expression rather than through decreasing PAF-R expression in pancreatic tissues.