 |
Previous Article | Next Article 
The Journal of Neuroscience, May 1, 1998, 18(9):3158-3170
Extrasynaptic Glutamate Diffusion in the Hippocampus:
Ultrastructural Constraints, Uptake, and Receptor Activation
Dmitri A.
Rusakov1 and
Dimitri M.
Kullmann2
1 Department of Biology, The Open University, Milton
Keynes MK7 6AA, United Kingdom, and 2 University Department
of Clinical Neurology, Institute of Neurology, University College
London, Queen Square, London WC1N 3BG, United Kingdom
Fast excitatory synapses are generally thought to act as private
communication channels between presynaptic and postsynaptic neurons.
Some recent findings, however, suggest that glutamate may diffuse out
of the synaptic cleft and bind to several subtypes of receptors, either
in the perisynaptic membrane or at neighboring synapses. It is not
known whether activation of these receptors can occur in response to
the release of a single vesicle of glutamate. Here we estimate the
spatiotemporal profile of glutamate in the extrasynaptic space after
vesicle exocytosis, guided by detailed ultrastructural measurements of
the CA1 neuropil in the adult rat. We argue that the vicinity of the
synapse can be treated as an isotropic porous medium, in which
diffusion is determined by the extracellular volume fraction and the
tortuosity factor, and develop novel stereological methods to estimate
these parameters. We also estimate the spatial separation between
synapses, to ask whether glutamate released at one synapse can activate
NMDA and other high-affinity receptors at a neighboring synapse.
Kinetic simulations of extrasynaptic glutamate uptake show that
transporters rapidly reduce the free concentration of transmitter.
Exocytosis of a single vesicle is, however, sufficient to bind to
high-affinity receptors situated in the immediate perisynaptic space.
The distance separating a typical synapse from its nearest neighbor is
~465 nm. Whether glutamate can reach a sufficient concentration to activate NMDA receptors at this distance depends critically on the
diffusion coefficient in the extracellular space. If diffusion is much
slower than in free aqueous solution, NMDA receptors could mediate
crosstalk between neighboring synapses.
Key words:
diffusion; spillover; tortuosity; extrasynaptic; transporters; AMPA; NMDA
Copyright © 1998 Society for Neuroscience 0270-6474/98/1893158-13$05.00/0
This article has been cited by other articles:

|
 |

|
 |
 
K. Zheng, A. Scimemi, and D. A. Rusakov
Receptor Actions of Synaptically Released Glutamate: The Role of Transporters on the Scale from Nanometers to Microns
Biophys. J.,
November 15, 2008;
95(10):
4584 - 4596.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
D. Atasoy, M. Ertunc, K. L. Moulder, J. Blackwell, C. Chung, J. Su, and E. T. Kavalali
Spontaneous and Evoked Glutamate Release Activates Two Populations of NMDA Receptors with Limited Overlap
J. Neurosci.,
October 1, 2008;
28(40):
10151 - 10166.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
M. Beato
The Time Course of Transmitter at Glycinergic Synapses onto Motoneurons
J. Neurosci.,
July 16, 2008;
28(29):
7412 - 7425.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
J. Glykys and I. Mody
The main source of ambient GABA responsible for tonic inhibition in the mouse hippocampus
J. Physiol.,
August 1, 2007;
582(3):
1163 - 1178.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
M. Postlethwaite, M. H. Hennig, J. R. Steinert, B. P. Graham, and I. D. Forsythe
Acceleration of AMPA receptor kinetics underlies temperature-dependent changes in synaptic strength at the rat calyx of Held
J. Physiol.,
February 15, 2007;
579(1):
69 - 84.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
L. P. Savtchenko and D. A. Rusakov
The optimal height of the synaptic cleft
PNAS,
February 6, 2007;
104(6):
1823 - 1828.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
E. D. Eggers and P. D. Lukasiewicz
Receptor and transmitter release properties set the time course of retinal inhibition.
J. Neurosci.,
September 13, 2006;
26(37):
9413 - 9425.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
R. G. Thorne and C. Nicholson
In vivo diffusion analysis with quantum dots and dextrans predicts the width of brain extracellular space
PNAS,
April 4, 2006;
103(14):
5567 - 5572.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
A. Scimemi, S. Schorge, D. M. Kullmann, and M. C. Walker
Epileptogenesis Is Associated With Enhanced Glutamatergic Transmission in the Perforant Path
J Neurophysiol,
February 1, 2006;
95(2):
1213 - 1220.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
J. M. Christie and C. E. Jahr
Multivesicular Release at Schaffer Collateral-CA1 Hippocampal Synapses
J. Neurosci.,
January 4, 2006;
26(1):
210 - 216.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
S. E. Lauri, M. Segerstrale, A. Vesikansa, F. Maingret, C. Mulle, G. L. Collingridge, J. T. R. Isaac, and T. Taira
Endogenous Activation of Kainate Receptors Regulates Glutamate Release and Network Activity in the Developing Hippocampus
J. Neurosci.,
May 4, 2005;
25(18):
4473 - 4484.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
J. S. Diamond
Deriving the Glutamate Clearance Time Course from Transporter Currents in CA1 Hippocampal Astrocytes: Transmitter Uptake Gets Faster during Development
J. Neurosci.,
March 16, 2005;
25(11):
2906 - 2916.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
J. R. Pugh and I. M. Raman
GABAA Receptor Kinetics in the Cerebellar Nuclei: Evidence for Detection of Transmitter from Distant Release Sites
Biophys. J.,
March 1, 2005;
88(3):
1740 - 1754.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
J.-i. Tanaka, M. Matsuzaki, E. Tarusawa, A. Momiyama, E. Molnar, H. Kasai, and R. Shigemoto
Number and Density of AMPA Receptors in Single Synapses in Immature Cerebellum
J. Neurosci.,
January 26, 2005;
25(4):
799 - 807.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
S. Raghavachari and J. E. Lisman
Properties of Quantal Transmission at CA1 Synapses
J Neurophysiol,
October 1, 2004;
92(4):
2456 - 2467.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
D. K. Binder, M. C. Papadopoulos, P. M. Haggie, and A. S. Verkman
In Vivo Measurement of Brain Extracellular Space Diffusion by Cortical Surface Photobleaching
J. Neurosci.,
September 15, 2004;
24(37):
8049 - 8056.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
A. Scimemi, A. Fine, D. M. Kullmann, and D. A. Rusakov
NR2B-Containing Receptors Mediate Cross Talk among Hippocampal Synapses
J. Neurosci.,
May 19, 2004;
24(20):
4767 - 4777.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
S. Lei and C. J. McBain
Two Loci of Expression for Long-Term Depression at Hippocampal Mossy Fiber-Interneuron Synapses
J. Neurosci.,
March 3, 2004;
24(9):
2112 - 2121.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
D. Grass, P. G. Pawlowski, J. Hirrlinger, N. Papadopoulos, D. W. Richter, F. Kirchhoff, and S. Hulsmann
Diversity of Functional Astroglial Properties in the Respiratory Network
J. Neurosci.,
February 11, 2004;
24(6):
1358 - 1365.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
W. Chen, V. Mahadomrongkul, U. V. Berger, M. Bassan, T. DeSilva, K. Tanaka, N. Irwin, C. Aoki, and P. A. Rosenberg
The Glutamate Transporter GLT1a Is Expressed in Excitatory Axon Terminals of Mature Hippocampal Neurons
J. Neurosci.,
February 4, 2004;
24(5):
1136 - 1148.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
Y. V. Pankratov and O. A. Krishtal
Distinct Quantal Features of AMPA and NMDA Synaptic Currents in Hippocampal Neurons: Implication of Glutamate Spillover and Receptor Saturation
Biophys. J.,
November 1, 2003;
85(5):
3375 - 3387.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
C. I. O. Myme, K. Sugino, G. G. Turrigiano, and S. B. Nelson
The NMDA-to-AMPA Ratio at Synapses Onto Layer 2/3 Pyramidal Neurons Is Conserved Across Prefrontal and Visual Cortices
J Neurophysiol,
August 1, 2003;
90(2):
771 - 779.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
M. Townsend, A. Yoshii, M. Mishina, and M. Constantine-Paton
Developmental loss of miniature N-methyl-D-aspartate receptor currents in NR2A knockout mice
PNAS,
February 4, 2003;
100(3):
1340 - 1345.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
D. E. Bergles, A. V. Tzingounis, and C. E. Jahr
Comparison of Coupled and Uncoupled Currents during Glutamate Uptake by GLT-1 Transporters
J. Neurosci.,
December 1, 2002;
22(23):
10153 - 10162.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
K. M. Franks, T. M. Bartol Jr., and T. J. Sejnowski
A Monte Carlo Model Reveals Independent Signaling at Central Glutamatergic Synapses
Biophys. J.,
November 1, 2002;
83(5):
2333 - 2348.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
K. P. Lehre and D. A. Rusakov
Asymmetry of Glia near Central Synapses Favors Presynaptically Directed Glutamate Escape
Biophys. J.,
July 1, 2002;
83(1):
125 - 134.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
T. Ichinose and P. D. Lukasiewicz
GABA Transporters Regulate Inhibition in the Retina by Limiting GABAC Receptor Activation
J. Neurosci.,
April 15, 2002;
22(8):
3285 - 3292.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
W. Chen, C. Aoki, V. Mahadomrongkul, C. E. Gruber, G. J. Wang, R. Blitzblau, N. Irwin, and P. A. Rosenberg
Expression of a Variant Form of the Glutamate Transporter GLT1 in Neuronal Cultures and in Neurons and Astrocytes in the Rat Brain
J. Neurosci.,
March 15, 2002;
22(6):
2142 - 2152.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
J. S. Diamond
Neuronal Glutamate Transporters Limit Activation of NMDA Receptors by Neurotransmitter Spillover on CA1 Pyramidal Cells
J. Neurosci.,
November 1, 2001;
21(21):
8328 - 8338.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
B. Barbour
An Evaluation of Synapse Independence
J. Neurosci.,
October 15, 2001;
21(20):
7969 - 7984.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
F. L. Kidd and J. T. R. Isaac
Kinetics and Activation of Postsynaptic Kainate Receptors at Thalamocortical Synapses: Role of Glutamate Clearance
J Neurophysiol,
September 1, 2001;
86(3):
1139 - 1148.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
E. Bracci, M. Vreugdenhil, S. P. Hack, and J. G. R. Jefferys
Dynamic Modulation of Excitation and Inhibition During Stimulation at Gamma and Beta Frequencies in the CA1 Hippocampal Region
J Neurophysiol,
June 1, 2001;
85(6):
2412 - 2422.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
J. E. Kacharmina, C. Job, P. Crino, and J. Eberwine
Stimulation of glutamate receptor protein synthesis and membrane insertion within isolated neuronal dendrites
PNAS,
October 10, 2000;
97(21):
11545 - 11550.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
K. C. Chen and C. Nicholson
Changes in brain cell shape create residual extracellular space volume and explain tortuosity behavior during osmotic challenge
PNAS,
July 5, 2000;
(2000)
150338197.
[Abstract]
[Full Text]
|
 |
|

|
 |

|
 |
 
J. S. Diamond and C. E. Jahr
Synaptically Released Glutamate Does Not Overwhelm Transporters on Hippocampal Astrocytes During High-Frequency Stimulation
J Neurophysiol,
May 1, 2000;
83(5):
2835 - 2843.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
T. L. Briones and B. Therrien
Behavioral Effects of Transient Cerebral Ischemia
Biol Res Nurs,
April 1, 2000;
1(4):
276 - 286.
[Abstract]
[PDF]
|
 |
|

|
 |

|
 |
 
D. W. Hochman and P. A. Schwartzkroin
Chloride-Cotransport Blockade Desynchronizes Neuronal Discharge in the "Epileptic" Hippocampal Slice
J Neurophysiol,
January 1, 2000;
83(1):
406 - 417.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
H. L. Atwood and J. M. Wojtowicz
Silent Synapses in Neural Plasticity: Current Evidence
Learn. Mem.,
November 1, 1999;
6(6):
542 - 571.
[Abstract]
[Full Text]
|
 |
|

|
 |

|
 |
 
N. Chery and Y. De Koninck
Junctional versus Extrajunctional Glycine and GABAA Receptor-Mediated IPSCs in Identified Lamina I Neurons of the Adult Rat Spinal Cord
J. Neurosci.,
September 1, 1999;
19(17):
7342 - 7355.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
M.-Y. Min, Z. Melyan, and D. M. Kullmann
Synaptically released glutamate reduces gamma -aminobutyric acid (GABA)ergic inhibition in the hippocampus via kainate receptors
PNAS,
August 17, 1999;
96(17):
9932 - 9937.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
R. Ventura and K. M. Harris
Three-Dimensional Relationships between Hippocampal Synapses and Astrocytes
J. Neurosci.,
August 15, 1999;
19(16):
6897 - 6906.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
J. E. Hanson and Y. Smith
Group I Metabotropic Glutamate Receptors at GABAergic Synapses in Monkeys
J. Neurosci.,
August 1, 1999;
19(15):
6488 - 6496.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
V. Aroniadou-Anderjaska, M. Ennis, and M. T. Shipley
Dendrodendritic Recurrent Excitation in Mitral Cells of the Rat Olfactory Bulb
J Neurophysiol,
July 1, 1999;
82(1):
489 - 494.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
J. A. Dzubay and C. E. Jahr
The Concentration of Synaptically Released Glutamate Outside of the Climbing Fiber-Purkinje Cell Synaptic Cleft
J. Neurosci.,
July 1, 1999;
19(13):
5265 - 5274.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
E. D'Angelo, P. Rossi, S. Armano, and V. Taglietti
Evidence for NMDA and mGlu Receptor-Dependent Long-Term Potentiation of Mossy Fiber-Granule Cell Transmission in Rat Cerebellum
J Neurophysiol,
January 1, 1999;
81(1):
277 - 287.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
J. C. Anderson, T. Binzegger, K. A. C. Martin, and K. S. Rockland
The Connection from Cortical Area V1 to V5: A Light and Electron Microscopic Study
J. Neurosci.,
December 15, 1998;
18(24):
10525 - 10540.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
R. Rao-Mirotznik, G. Buchsbaum, and P. Sterling
Transmitter Concentration at a Three-Dimensional Synapse
J Neurophysiol,
December 1, 1998;
80(6):
3163 - 3172.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
K. P. Lehre and N. C. Danbolt
The Number of Glutamate Transporter Subtype Molecules at Glutamatergic Synapses: Chemical and Stereological Quantification in Young Adult Rat Brain
J. Neurosci.,
November 1, 1998;
18(21):
8751 - 8757.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
D. E. Bergles and C. E. Jahr
Glial Contribution to Glutamate Uptake at Schaffer Collateral-Commissural Synapses in the Hippocampus
J. Neurosci.,
October 1, 1998;
18(19):
7709 - 7716.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
D. A. Rusakov and D. M. Kullmann
Geometric and viscous components of the tortuosity of the extracellular space in the brain
PNAS,
July 21, 1998;
95(15):
8975 - 8980.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
K. C. Chen and C. Nicholson
Changes in brain cell shape create residual extracellular space volume and explain tortuosity behavior during osmotic challenge
PNAS,
July 18, 2000;
97(15):
8306 - 8311.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
L.-Y. Wang
The Dynamic Range for Gain Control of NMDA Receptor-Mediated Synaptic Transmission at a Single Synapse
J. Neurosci.,
December 15, 2000;
20(24):
RC115 - RC115.
[Abstract]
[Full Text]
[PDF]
|
 |
|
|