Imaging Glutamate with Genetically Encoded Fluorescent Sensors

  • Gerard J. BroussardEmail author
  • Elizabeth K. Unger
  • Ruqiang Liang
  • Brian P. McGrew
  • Lin TianEmail author
Part of the Neuromethods book series (NM, volume 130)


Superimposed on the vast and complex synaptic network is a largely invisible set of chemical inputs, such as neurotransmitters and neuromodulators, that exert a profound influence on brain function across many structures and temporal scales. Thus, the determination of the spatiotemporal relationships between these chemical signals with synaptic resolution in the intact brain is essential to decipher the codes for transferring information across circuitry and systems. Recent advances in imaging technology have been employed to determine the extent of spatial and temporal neurotransmitter dynamics in the brain, especially glutamate, the most abundant excitatory neurotransmitter. Here, we discuss recent imaging approaches, particularly with a focus on the design and application of genetically encoded indicator iGluSnFR, in analyzing glutamate transients in vitro, ex vivo, and in vivo.

Key words

Glutamate iGluSnFR Fluorescent sensor Genetically encoded indicators of neural activity Protein engineering Fluorescent functional imaging 



This work is supported by NIH DP2 MH107059 (L.T.), Brain Initiative U01NS090604 (L.T., E.K.U., G.J.B.) and U01NS09058 (R.L.), Rita Allen Foundation (R.L.), Human Frontier Research Program (G.J.B.), and NIH R21NS095325 (B.P.M.). We are grateful for the contributions of Douglas Unger in generating the rotation matrix. We are grateful to Loren Looger, Jonathan Marvin and Philip Borden for their pioneering work in engineering iGluSnFR and critical comments. We also thank Lisa Makhoul for careful reading and discussion of this book chapter.


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© Springer Science+Business Media LLC 2018

Authors and Affiliations

  1. 1.Department of Biochemistry and Molecular MedicineUniversity of California DavisDavisUSA
  2. 2.Neuroscience Graduate GroupUniversity of California DavisDavisUSA

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