title: Transport of AMPA receptors during long-term potentiation is impaired in rats with hepatic encephalopathy.
abstract: Cognitive function is impaired in patients with hepatic encephalopathy. Learning ability is also impaired in rats with hepatic encephalopathy due to portacaval shunts. Long-term potentiation (LTP) in hippocampus, considered the basis of some forms of learning and memory, is impaired in rats with portacaval shunt. We analyzed the mechanisms by which LTP is impaired in these rats. In control rats, application of the tetanus to induce LTP increases phosphorylation of Thr286 of calcium-calmodulin dependent protein kinase II. This activates the kinase which phosphorylates the GluR1 subunit of AMPA receptors in Ser831 and induces its translocation to the post-synaptic densities. All these steps are completely prevented in rats with hepatic encephalopathy in which the tetanus does not induce phosphorylation of CaMKII or GluR1 nor translocation of this subunit to the post-synaptic membrane. This would explain the impairment in LTP in these rats.
authors.affiliation: Centro de Investigación Príncipe Felipe, Valencia, Spain.
authors.forename: Pilar
authors.initials: P
authors.lastname: Monfort
authors.forename: Blanca
authors.initials: B
authors.lastname: Piedrafita
authors.forename: Vicente
authors.initials: V
authors.lastname: Felipo
mesh_terms: D000818:Animals; D015153:Blotting, Western; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000378:metabolism; D000076122:Disks Large Homolog 4 Protein; D004558:Electric Stimulation; D006501:Hepatic Encephalopathy / Q000378:metabolism*; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D017774:Long-Term Potentiation / Q000502:physiology*; D008297:Male; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D051381:Rats; D017208:Rats, Wistar; D018091:Receptors, AMPA / Q000235:genetics / Q000378:metabolism*; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism
chemical_list: D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D000076122:Disks Large Homolog 4 Protein; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D018091:Receptors, AMPA; C501449:Dlg4 protein, rat; C104722:glutamate receptor ionotropic, AMPA 2