 |
Previous Article | Next Article 
The Journal of Neuroscience, January 15, 1998, 18(2):658-671
Stability in Synapse Number and Size at 2 Hr after Long-Term
Potentiation in Hippocampal Area CA1
Karin E.
Sorra and
Kristen M.
Harris
Program in Neuroscience, Harvard Medical School, and Division of
Neuroscience in the Department of Neurology, Children's Hospital,
Boston, Massachusetts 02115
Long-term potentiation (LTP) is an important model for examining
synaptic mechanisms of learning and memory. A key question is whether
the enhanced synaptic transmission occurring with LTP involves the
addition of new synapses, the enlargement of existing synapses, or a
redistribution in synaptic weight among synapses. Two experimental
designs were used to address this question. In the first experimental
design three conditions were evaluated across hippocampal slices
maintained in vitro, including slices with LTP analyzed
at 2 hr post-tetanus, slices tetanized in the presence of APV, and
control slices receiving test stimulation only. In the second
experimental design independent LTP and control (low-frequency
stimulation) sites were examined. Synapse density was estimated by an
unbiased volume sampling procedure. Synapse size was computed by
three-dimensional reconstruction from serial electron microscopy (EM).
Serial EM also was used to compute synapse number per unit length of
dendrite. In both experimental designs there were no significant
effects of LTP on total synapse number, on the distribution of
different types of synapses (thin, mushroom, stubby, or branched
dendritic spines and macular, perforated, or segmented postsynaptic
densities), on the frequency of shaft synapses, nor on the relative
proportion of single or multiple synapse axonal boutons. There was also
no increase in synapse size. These results suggest that LTP does not
cause an overall formation of new synapses nor an enlargement of
synapses at 2 hr post-tetanus in hippocampal area CA1, and these
results support the hypothesis that LTP could involve a redistribution
of synaptic weights among existing synapses.
Key words:
long-term potentiation; hippocampus; area CA1; serial
electron microscopy; dendritic spines; postsynaptic density; disector; axonal boutons; three-dimensional reconstructions; ultrastructure; hippocampal slice; in vitro
Copyright © 1998 Society for Neuroscience 0270-6474/98/182658-14$05.00/0
This article has been cited by other articles:

|
 |

|
 |
 
U. V. Nagerl, G. Kostinger, J. C. Anderson, K. A. C. Martin, and T. Bonhoeffer
Protracted Synaptogenesis after Activity-Dependent Spinogenesis in Hippocampal Neurons
J. Neurosci.,
July 25, 2007;
27(30):
8149 - 8156.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
L. Y. Chen, C. S. Rex, M. S. Casale, C. M. Gall, and G. Lynch
Changes in Synaptic Morphology Accompany Actin Signaling during LTP
J. Neurosci.,
May 16, 2007;
27(20):
5363 - 5372.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
G. Lynch, E. A. Kramar, C. S. Rex, Y. Jia, D. Chappas, C. M. Gall, and D. A. Simmons
Brain-Derived Neurotrophic Factor Restores Synaptic Plasticity in a Knock-In Mouse Model of Huntington's Disease
J. Neurosci.,
April 18, 2007;
27(16):
4424 - 4434.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
C. D. Kopec, B. Li, W. Wei, J. Boehm, and R. Malinow
Glutamate Receptor Exocytosis and Spine Enlargement during Chemically Induced Long-Term Potentiation
J. Neurosci.,
February 15, 2006;
26(7):
2000 - 2009.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
C. Lang, A. Barco, L. Zablow, E. R. Kandel, S. A. Siegelbaum, and S. S. Zakharenko
Transient expansion of synaptically connected dendritic spines upon induction of hippocampal long-term potentiation
PNAS,
November 23, 2004;
101(47):
16665 - 16670.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
J. H. Schwartz
Ubiquitination, Protein Turnover, and Long-Term Synaptic Plasticity
Sci. Signal.,
July 8, 2003;
2003(190):
pe26 - pe26.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
G. W. Huntley, O. Gil, and O. Bozdagi
The Cadherin Family of Cell Adhesion Molecules: Multiple Roles in Synaptic Plasticity
Neuroscientist,
June 1, 2002;
8(3):
221 - 233.
[Abstract]
[PDF]
|
 |
|

|
 |

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

|
 |

|
 |
 
A. Dosemeci, J.-H. Tao-Cheng, L. Vinade, C. A. Winters, L. Pozzo-Miller, and T. S. Reese
Glutamate-induced transient modification of the postsynaptic density
PNAS,
August 17, 2001;
(2001)
181336998.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
J. C. Fiala and K. M. Harris
Extending Unbiased Stereology of Brain Ultrastructure to Three-dimensional Volumes
J. Am. Med. Inform. Assoc.,
January 1, 2001;
8(1):
1 - 16.
[Abstract]
[Full Text]
|
 |
|

|
 |

|
 |
 
B. E. Chen, B. Lendvai, E. A. Nimchinsky, B. Burbach, K. Fox, and K. Svoboda
Imaging High-Resolution Structure of GFP-Expressing Neurons in Neocortex In Vivo
Learn. Mem.,
November 1, 2000;
7(6):
433 - 441.
[Abstract]
[Full Text]
|
 |
|

|
 |

|
 |
 
M.-S. Rioult-Pedotti, D. Friedman, and J. P. Donoghue
Learning-Induced LTP in Neocortex
Science,
October 20, 2000;
290(5491):
533 - 536.
[Abstract]
[Full Text]
|
 |
|

|
 |

|
 |
 
Y. Geinisman
Structural Synaptic Modifications Associated with Hippocampal LTP and Behavioral Learning
Cereb Cortex,
October 1, 2000;
10(10):
952 - 962.
[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]
|
 |
|

|
 |

|
 |
 
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]
|
 |
|

|
 |

|
 |
 
S. E. McKay, A. L. Purcell, and T. J. Carew
Regulation of Synaptic Function by Neurotrophic Factors in Vertebrates and Invertebrates: Implications for Development and Learning
Learn. Mem.,
May 1, 1999;
6(3):
193 - 215.
[Abstract]
[Full Text]
|
 |
|

|
 |

|
 |
 
S. A. Kirov, K. E. Sorra, and K. M. Harris
Slices Have More Synapses than Perfusion-Fixed Hippocampus from both Young and Mature Rats
J. Neurosci.,
April 15, 1999;
19(8):
2876 - 2886.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
M. Maletic-Savatic, R. Malinow, and K. Svoboda
Rapid Dendritic Morphogenesis in CA1 Hippocampal Dendrites Induced by Synaptic Activity
Science,
March 19, 1999;
283(5409):
1923 - 1927.
[Abstract]
[Full Text]
|
 |
|

|
 |

|
 |
 
S. E. Lauri, S. Kaukinen, T. Kinnunen, A. Ylinen, S. Imai, K. Kaila, T. Taira, and H. Rauvala
Reg1ulatory Role and Molecular Interactions of a Cell-Surface Heparan Sulfate Proteoglycan (N-syndecan) in Hippocampal Long-Term Potentiation
J. Neurosci.,
February 15, 1999;
19(4):
1226 - 1235.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
A. Shimada, C. A. Mason, and M. E. Morrison
TrkB Signaling Modulates Spine Density and Morphology Independent of Dendrite Structure in Cultured Neonatal Purkinje Cells
J. Neurosci.,
November 1, 1998;
18(21):
8559 - 8570.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
G. M. G. Shepherd and K. M. Harris
Three-Dimensional Structure and Composition of CA3right-arrowCA1 Axons in Rat Hippocampal Slices: Implications for Presynaptic Connectivity and Compartmentalization
J. Neurosci.,
October 15, 1998;
18(20):
8300 - 8310.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
A. Dosemeci, J.-H. Tao-Cheng, L. Vinade, C. A. Winters, L. Pozzo-Miller, and T. S. Reese
Glutamate-induced transient modification of the postsynaptic density
PNAS,
August 28, 2001;
98(18):
10428 - 10432.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
P. J. Mackenzie, G. S. Kenner, O. Prange, H. Shayan, M. Umemiya, and T. H. Murphy
Ultrastructural Correlates of Quantal Synaptic Function at Single CNS Synapses
J. Neurosci.,
June 15, 1999;
19(12):
RC13 - RC13.
[Abstract]
[Full Text]
[PDF]
|
 |
|
|