<> "The repository administrator has not yet configured an RDF license."^^ . <> . . "Micro-Electrode-Array recordings : a tool to study calcium signaling pathways involved in neuronal network plasticity and late phase long-term potentiation"^^ . "The molecular mechanisms of many biological signaling pathways are highly conserved in evolution and are, often, regulated by second messengers. One of the most important second messengers is calcium, Ca2+. The huge diversity of calcium-regulated signaling pathways spans from fertilization of the oocyte over the activation of the immune system right up to the activity-regulated transmitter release in neurons. Furthermore, it is known that in cultured neurons, increases in nuclear calcium concentrations are of vital importance for CREB-mediated gene transcription. Those genes control, among other phenomena, neuronal survival and certain forms of learning and memory. The hippocampal formation is essential for spatial memory and associative learning, and has been extensively characterized in terms of its circuitry and molecular mechanisms which underlie plasticity. The potentiation of Schaffer collateral – CA1 synapses by the activation of NMDAR-mediated postsynaptic signaling cascades is known as long-term potentiation (LTP) and serves as a model for learning and memory in the mammalian central nervous system. The induction of LTP requires postsynaptic calcium influx, the activation of calcium-dependent kinases and relative signaling cascades. These processes are now well-understood but less is known about the mechanisms which make LTP persistent for hours and days. The objective of this study was to establish procedures, by means of Micro-Electrode-Arrays (MEAs), which allow studying especially the signaling pathways involved in the CREB-regulated transcription-dependent late phase of LTP (L-LTP). In one study I cultured primary hippocampal neurons for two weeks on MEAs and analyzed spontaneous activity of these networks by extracellular recordings. The spontaneous activity pattern strongly influences neuronal network information processing and thus modulation of neuronal network activity, e.g. upon external stimulations, is likely to be a basic feature of processes involved in learning and memory. In this part I could show that the specific inhibition of nuclear calcium signaling (and the associated inhibition of CREB-mediated gene transcription) alters the periodic activity pattern of developing neuronal networks. Moreover, I demonstrated that one target gene of the nuclear calcium signaling pathway, vegf-d, is involved in keeping neuronal networks fire. Interestingly, so far VEGF-D has been mainly known as a growth factor important for angiogenesis and lymphatogenesis. In another study I tried to transfer the results of my work on neuronal networks to acute slice preparations, a system closer to the in vivo condition. Acute hippocampal slices enabled detailed studies concerning the initiation of LTP but less is known about the mechanisms that make LTP persist for extended time periods. This is partly due to the difficulty of maintaining stable recordings over several hours from acute slice preparations. MEAs offer stable extracellular field recordings from many points on a brain slice. I could show that on MEAs LTP induced by high-frequency stimulation lasted four hours and longer, and was NMDA receptor- as well as translation-sensitive. To investigate whether the expression of late phase LTP is nuclear calcium-sensitive and which genes exactly are necessary for the maintenance phase of LTP I established virus-mediated gene transfer into the hippocampus of adult rats to generate genetically modified animals. In summary, I established two novel methods suitable to investigate especially the signaling pathways important for the maintenance phase of LTP in hippocampal neurons. Both methods can be used to screen for candidate genes involved in L-LTP. "^^ . "2009" . . . . . . . . "Eckehard"^^ . "Freitag"^^ . "Eckehard Freitag"^^ . . . . . . "Micro-Electrode-Array recordings : a tool to study calcium signaling pathways involved in neuronal network plasticity and late phase long-term potentiation (PDF)"^^ . . . "PhD_Thesis_Eckehard_Freitag.pdf"^^ . . . "Micro-Electrode-Array recordings : a tool to study calcium signaling pathways involved in neuronal network plasticity and late phase long-term potentiation (Other)"^^ . . . . . . "indexcodes.txt"^^ . . . "Micro-Electrode-Array recordings : a tool to study calcium signaling pathways involved in neuronal network plasticity and late phase long-term potentiation (Other)"^^ . . . . . . "lightbox.jpg"^^ . . . "Micro-Electrode-Array recordings : a tool to study calcium signaling pathways involved in neuronal network plasticity and late phase long-term potentiation (Other)"^^ . . . . . . "preview.jpg"^^ . . . "Micro-Electrode-Array recordings : a tool to study calcium signaling pathways involved in neuronal network plasticity and late phase long-term potentiation (Other)"^^ . . . . . . "medium.jpg"^^ . . . "Micro-Electrode-Array recordings : a tool to study calcium signaling pathways involved in neuronal network plasticity and late phase long-term potentiation (Other)"^^ . . . . . . "small.jpg"^^ . . "HTML Summary of #12436 \n\nMicro-Electrode-Array recordings : a tool to study calcium signaling pathways involved in neuronal network plasticity and late phase long-term potentiation\n\n" . "text/html" . . . "570 Biowissenschaften, Biologie"@de . "570 Life sciences"@en . .