title: Alterations of corticostriatal plasticity by ammonium and rescue by green tea polyphenols.
abstract: Hyperammonemia is a major pathophysiological factor in encephalopathies associated with acute and chronic liver failure. On mouse brain slice preparations we analyzed the effects of ammonium on the characteristics of corticostriatal long-term potentiation (LTP) induced by high-frequency electrical stimulation (HFS) of cortical input and the long-lasting effects of pharmacological NMDA receptor (NMDAR) activation. Ammonium chloride exposure enhanced the expression of HFS-induced LTP at the expense of LTD and promoted the generation of NMDA-induced LTD. This treatment did not affect two NMDAR-independent forms of plasticity: taurine-induced LTP and histamine-induced LTD. Alterations in NMDA-induced plasticity were prevented by treatment with green tea polyphenols suggesting the contribution of oxidative stress to the expression of abnormal corticostriatal plasticity.
authors: Department of Neurophysiology, Heinrich-Heine-University, D - 40204 Dusseldorf, Germany.
authors: Aisa N
authors: AN
authors: Chepkova
authors: Olga A
authors: OA
authors: Sergeeva
authors: Helmut L
authors: HL
authors: Haas
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000737:chemistry / Q000494:pharmacology*; D002392:Catechin / Q000737:chemistry / Q000494:pharmacology; D003342:Corpus Striatum / Q000187:drug effects* / Q000502:physiology*; D004558:Electric Stimulation; D006632:Histamine / Q000378:metabolism; D022124:Hyperammonemia / Q000378:metabolism; D036881:Long-Term Synaptic Depression / Q000187:drug effects*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D059808:Polyphenols / Q000737:chemistry / Q000494:pharmacology*; D000644:Quaternary Ammonium Compounds / Q000378:metabolism*; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism; D013654:Taurine / Q000378:metabolism; D013662:Tea / Q000737:chemistry
chemical_list: D000975:Antioxidants; D059808:Polyphenols; D000644:Quaternary Ammonium Compounds; D016194:Receptors, N-Methyl-D-Aspartate; D013662:Tea; D013654:Taurine; D006632:Histamine; D002392:Catechin
keywords: Ammonium; Green tea polyphenols; Long-term depression; Long-term potentiation; NMDA; Striatum