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SciLifeLab The Svedberg seminar series, Dmitri Rusakov, Plasticity of synaptic microenvironment

Monday, December 17

Dmitri Rusakov

Institute of Neurology, University College London (UCL), London, UK.

Dmitri Rusakov obtained his PhD in Biophysics / Neurobiology in 1988 from Bogomoletz Institute of Physiology (Kiev). He moved to the UK to work with Mike Stewart and Steven Rose (The Open University) and Tim Bliss and Alan Fine (National Institute for Medical Research, London), before starting an independent career (MRC Career Award) in 1999. Since 2000 has been at University College London Institute of Neurology. Obtained Wellcome Trust Senior Fellowship in 2003 and in 2008, appointed Professor (Chair) of Neuroscience in 2007. Elected to Academia Europaea in 2012, in 2013 obtained Wellcome Trust Principal Fellowship and an ERC Advanced Grant. Research interests include mechanisms of central synaptic transmission, formation of memory trace, astroglia-neuron communication, and principles of signal integration in the brain, in health and disease.

Title of the talk: Activity-dependent plasticity of synaptic microenvironment

Receptor actions of glutamate escaping the synaptic cleft play an important role in excitatory signal integration across central neural circuits, also impacting on brain cognitive function. The degree of glutamate escape is critically controlled by astroglia which also generate molecular signals essential for induction of synaptic plasticity. Whether perisynaptic astrocyte processes also undergo plastic changes remains poorly understood. We monitored perisynaptic astroglia using light diffraction-insensitive microscopy methods and found that the induction of a classical synaptic memory paradigm, long-term potentiation (LTP), in situ and in vivo, triggers astroglial withdrawal from potentiated synapses. Optical glutamate sensors combined with single-cell electrophysiology in situ revealed that LTP-triggered astroglial withdrawal facilitates extrasynaptic glutamate escape boosting NMDA receptor-mediated cross-talk among neighbouring synapses. This phenomenon depends on astroglial NKCC1 transporters and successful LTP induction whereas the latter does not require astrocyte morphogenesis. Thus, induction of synaptic plasticity also engages an astroglial mechanism regulating glutamate signalling landscape in local micro-circuits of the brain.

Read more about Dmitri Rusakov´s research

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