Ischemic LTP: NMDA-dependency and dorso/ventral distribution within the hippocampus.
A transient ischemic episode causes a reduction in evoked EPSPs in hippocampal slices, followed by an NMDA dependent LTP. We explored the relations between ischemic LTP (iLTP) and the more conventional tetanic LTP (tLTP) in CA1 region of slices along the dorsal/ventral axis of the hippocampus. Dorsal hippocampal (DH) slices produced a much larger iLTP than their ventral hippocampal (VH) counterparts. In both regions, iLTP and tLTP shared the same NMDA mediated potentiation, such that one LTP saturated the ability of the other treatment to generate LTP. The smaller LTP in VH was correlated with a lower NMDA-mediated EPSP, and a parallel lower density of NMDA receptors. Calcium permeable AMPA receptors did not contribute to the DH/VH disparity. We conclude that a differential distribution of NMDA receptor subunits along the septotemporal axis of the hippocampus controls the diverse ability to evoke iLTP and tLTP in the two regions and may underlie their characteristic behavioral outputs as well as their differential sensitivity to ischemia.
Talpiot Medical Leadership Program, The Chaim Sheba Medical Center, Tel HaShomer, Israel.|Department of Neurology, The J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Nicola
N
Maggio
Department of Neurology, The J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Efrat
E
Shavit Stein
Department of Neurobiology, the Weizmann Institute of Science, Rehovot, Israel.
Menahem
M
Segal
D000818:Animals; D002545:Brain Ischemia / Q000503:physiopathology*; D056547:CA1 Region, Hippocampal / Q000503:physiopathology*; D004558:Electric Stimulation; D017774:Long-Term Potentiation / Q000502:physiology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018091:Receptors, AMPA / Q000502:physiology; D016194:Receptors, N-Methyl-D-Aspartate / Q000502:physiology*
D018091:Receptors, AMPA; D016194:Receptors, N-Methyl-D-Aspartate
LTP; NMDA receptors; dorsal hippocampus; ischemic LTP