title: Postsynaptically synthesized prostaglandin E2 (PGE2) modulates hippocampal synaptic transmission via a presynaptic PGE2 EP2 receptor.
abstract: Increasing evidence suggests that cyclooxygenase-2 (COX-2) is involved in synaptic transmission and plasticity, and prostaglandin E2 (PGE2) is a key molecule in COX-2-meduated synaptic modification. However, the precise mechanisms, in particular, which subtypes of PGE2 receptors (EPs) mediate the PGE2-induced synaptic response, are not clear. Recently, we demonstrated that EPs are expressed heterogeneously in the hippocampus, and EP2/4 are mainly expressed in presynaptic terminals. Here, we report that PGE2 increased synaptic stimulus-evoked amplitudes of EPSPs in hippocampal slices and frequency of miniature EPSCs (mEPSCs) in hippocampal neurons in culture. These actions were mimicked by an EP2 agonist and attenuated by protein kinase A inhibitors. Decrease of EP2 expression through silencing the EP2 gene eliminated PGE2-induced increase of the frequency of mEPSCs. COX-2 and microsomal PGE synthase-1 (mPGES-1) and mPGES-2 are present in postsynaptic dendritic spines, because they are colocalized with PSD-95 (postsynaptic density-95), a postsynaptic marker. In addition, the frequency of mEPSCs was enhanced in neurons pretreated with interleukin-1beta or lipopolysaccharide, which elevated expression of COX-2 and mPGES-1 and produced PGE2, and this enhancement was inhibited by a COX-2 inhibitor that inhibited production of PGE2. Our results suggest that PGE2 synthesized by postsynaptically localized COX-2 functions as a retrograde messenger in hippocampal synaptic signaling via a presynaptic EP2 receptor.
authors.affiliation: Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112, USA.
authors.forename: Nan
authors.initials: N
authors.lastname: Sang
authors.forename: Jian
authors.initials: J
authors.lastname: Zhang
authors.forename: Victor
authors.initials: V
authors.lastname: Marcheselli
authors.forename: Nicolas G
authors.initials: NG
authors.lastname: Bazan
authors.forename: Chu
authors.initials: C
authors.lastname: Chen
mesh_terms: D000818:Animals; D051546:Cyclooxygenase 2 / Q000378:metabolism; D000076122:Disks Large Homolog 4 Protein; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004558:Electric Stimulation / Q000379:methods; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D005455:Fluorescent Antibody Technique / Q000379:methods; D006624:Hippocampus / Q000166:cytology*; D066298:In Vitro Techniques; D007375:Interleukin-1 / Q000494:pharmacology; D047908:Intracellular Signaling Peptides and Proteins; D008070:Lipopolysaccharides / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D008565:Membrane Proteins; D051379:Mice; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D018408:Patch-Clamp Techniques / Q000379:methods; D000072483:Placenta Growth Factor; D011257:Pregnancy Proteins / Q000378:metabolism; D017729:Presynaptic Terminals / Q000378:metabolism*; D011459:Prostaglandins E, Synthetic / Q000494:pharmacology*; D012333:RNA, Messenger / Q000096:biosynthesis; D034741:RNA, Small Interfering / Q000494:pharmacology; D018078:Receptors, Prostaglandin E / Q000502:physiology*; D058307:Receptors, Prostaglandin E, EP2 Subtype; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D013569:Synapses / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*; D013997:Time Factors
chemical_list: D000076122:Disks Large Homolog 4 Protein; C501449:Dlg4 protein, rat; D004791:Enzyme Inhibitors; D007375:Interleukin-1; D047908:Intracellular Signaling Peptides and Proteins; D008070:Lipopolysaccharides; D008565:Membrane Proteins; C000608037:Pgf protein, mouse; C000608038:Pgf protein, rat; D011257:Pregnancy Proteins; D011459:Prostaglandins E, Synthetic; C545645:Ptger2 protein, mouse; C545646:Ptger2 protein, rat; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D018078:Receptors, Prostaglandin E; D058307:Receptors, Prostaglandin E, EP2 Subtype; D000072483:Placenta Growth Factor; D051546:Cyclooxygenase 2; C489691:Ptgs2 protein, rat