Platelet-Activating Factor in Brain Regions After Transient Ischemia in Gerbils

BACKGROUND AND PURPOSE: Platelet-activating factor (PAF) has been reported to be an active mediator in ischemic brain damage on the basis of indirect pharmacological data from PAF antagonists. The direct measurement of PAF in neuronal tissues has not been reported previously in analogous animal models. We have examined regional brain PAF concentration changes during the reperfusion period after ischemia in gerbils to obtain direct evidence for the involvement of PAF with ischemic brain damage and reported gas chromatography/mass spectrometry (GC/MS) methods of PAF quantitative analysis in brain tissues. METHODS: After transient (10 minutes) ischemia followed by controlled periods (0 to 96 hours) of reperfusion and recovery, regional PAF concentrations were determined in gerbil brain tissue. Quantitative analysis of PAF in brain regions is performed using an electron-capture negative chemical ionization GC/MS method, modified for brain tissue. RESULTS: The level of PAF was increased significantly and maximally in hippocampus (211%), cortex (168%), and thalamus (169%) after 1 hour of reperfusion. In contrast, there were no significant changes of PAF in any brain region from 6 hours to 96 hours after reperfusion. CONCLUSIONS: PAF is increased in gerbil brain in response to ischemia at early stages of reperfusion. PAF increases could contribute to the onset and progress of ischemic neuropathology.