Masashi Umemiya
Tohoku University
7 Papers
38 Citations
Masashi Umemiya is an academic researcher from Tohoku University. The author has contributed to research in topics: Excitatory postsynaptic potential & NMDA receptor. The author has an hindex of 7, co-authored 7 publications. Previous affiliations of Masashi Umemiya include University of British Columbia.
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Papers
A Calcium-Dependent Feedback Mechanism Participates in Shaping Single NMDA Miniature EPSCs
TL;DR: Trial-to-trial amplitude variability of miniature calcium transients mediated by NMDARs increased with the injection of exogenous calcium buffers, suggesting that the amplitude of synaptic calciumTransients are maintained at a rather constant level by a calcium-mediated feedback mechanism.
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Ca2+ Imaging of CNS Axons in Culture Indicates Reliable Coupling between Single Action Potentials and Distal Functional Release Sites
TL;DR: It is concluded that the coupling of somatic action potentials to distal release sites is generally a reliable process, although nonlinearity in the relationship between Ca2+ influx and neurotransmitter release may amplify the effects of relatively small fluctuations in Ca2- influx.
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Behaviour of NMDA and AMPA receptor-mediated miniature EPSCs at rat cortical neuron synapses identified by calcium imaging.
TL;DR: It is suggested that factors effecting both receptor classes, such as the amount of transmitter in synaptic vesicles, might contribute to the variation in mEPSC amplitude during repeated miniature events at a single synapse.
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Ultrastructural correlates of quantal synaptic function at single CNS synapses.
Paul J. Mackenzie,Gail S. Kenner,Oliver Prange,Hossein Shayan,Masashi Umemiya,Timothy H. Murphy +5 more
TL;DR: Results demonstrate that synapse size correlates positively with the amplitude of the NMDA receptor-mediated postsynaptic response, suggesting that larger synapses express a greater number of NMDA receptors, and regulation of quantal amplitude may involve processes that altersynapse size.
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Distinct immunohistochemical localization of two isoforms of Ca2+/calmodulin-dependent protein kinase kinases in the adult rat brain.
TL;DR: The distinct localization of two isoforms of CaM‐KKs suggests that the complicated mechanisms for activation of Ca2+/calmodulin‐dependent protein kinase IV by CaM-KKs may be exerted in region‐specific manners as well as intracellularly.