BACKGROUND: Prostaglandin E2(PGE2)can directly regulate toxic injury of hippcampal neurons throgh particpation by its receptor.Increase of excitability of hippocampal membrane and long-term synaptic elasticity are closely related to PGE2,PGD2 and PGF2A.This suggests that PGE2 may be a key molecule of neuronal signal passage and regulate the existence of neurons theough its receptor.However,which isoforms of PGE2 recptor expressing in hippocampal neurons is still unclear.OBJECTIVE: To research the subtype expression of PGE2 receptor in hippocampus of rats throgh mRNA transcription and protein interpretation.DESIGN: Animal studies with random,control and operator and designer double-blind methods.SETTING: University of South Carolina,Animal Center.MATERIALS: Sprague-Dawley rats,aged 12 weeks ,weighing 200 g,females 48 and males 48 ,were selected from Animal Center in South Carolina University,Tri ReagentTM kit was provided by Molecular Research Center,USA.METHODS:The experiment was carried out in Animal Center in South Carolina University from January to December 2005.The expression of the PGE2 receptors was profiled and compared in rat hippocampus using real-time RT-PCR and West-blot techniques.MAIN OUTCOME MEASURES:Expression of PGE2 receptors in various isoforms of hippocampal neurons of rats.RESULTS:mRNAs of all four Ep1-4 subtypes were detected in the hippocampus.West-blot data showed consistently detectable bands at approximately Mr 50 000 of EP1,Mr 40 000 and Mr 52 000 of EP2,Mr 45 000,M 57 000 and Mr 105 000 of EP3, and Mr 46 000 of EP4.CONCLUSION:Identifying four subtypes of Eps heterogeneously expresses in the hippocampus.