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Selective acquisition of AMPA receptors over postnatal development suggests a molecular basis for silent synapses


Early in postnatal development, glutamatergic synapses transmit primarily through NMDA receptors. As development progresses, synapses acquire AMPA receptor function. The molecular basis of these physiological observations is not known. Here we examined single excitatory synapses with immunogold electron–microscopic analysis of AMPA and NMDA receptors along with electrophysiological measurements. Early in postnatal development, a significant fraction of excitatory synapses had NMDA receptors and lacked AMPA receptors. As development progressed, synapses acquired AMPA receptors with little change in NMDA receptor number. Thus, synapses with NMDA receptors but no AMPA receptors can account for the electrophysiologically observed 'silent synapse'.

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Figure 1: Immunogold labeling of NMDA receptors in the CA1 stratum radiatum of the hippocampus.
Figure 4: Frequency distribution of AMPA and NMDA–R immunogold labeling, observed and fit by the low–detection model.
Figure 2: Immunogold labeling of AMPA receptors in the CA1 stratum radiatum of the hippocampus.
Figure 3: AMPA–R immunolabeling in high–sensitivity conditions.
Figure 5: Frequency distributions of AMPA–R immunogold particles with high–sensitivity immunolabeling conditions.
Figure 6: Amplitude of focally evoked miniature excitatory postsynaptic currents does not change with development.

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  1. Hollmann, M. & Heinemann, S. Cloned glutamate receptors. Annu. Rev. Neurosci. 17, 31–108 (1994).

    Article  CAS  Google Scholar 

  2. Liao, D. & Malinow, R. Deficiency in induction but not expression of LTP in hippocampal slices from young rats. Learn. Mem. 3, 138–149 ( 1996).

    Article  CAS  Google Scholar 

  3. Durand, G., Kovalchuk, Y. & Konnerth, A. Long–term potentiation and functional synapse induction in developing hippocampus. Nature 381, 71–75 (1996).

    Article  CAS  Google Scholar 

  4. Hsia, A. Y., Malenka, R. C. & Nicoll, R. A. Development of excitatory circuitry in the hippocampus. J. Neurophysiol. 79, 2013– 2024 (1998).

    Article  CAS  Google Scholar 

  5. Wu, G.–Y., Malinow, R. & Cline, H. T. Maturation of a central glutamatergic synapse. Science 274, 972–976 ( 1996).

    Article  CAS  Google Scholar 

  6. Isaac, J. T., Crair, M. C., Nicoll, R. A. & Malenka, R. C. Silent synapses during development of thalamocortical inputs. Neuron 18, 269–280 ( 1997).

    Article  CAS  Google Scholar 

  7. Liao, D., Hessler, N. A. & Malinow, R. Activation of postsynaptically silent synapses during pairing–induced LTP in CA1 region of hippocampal slice. Nature 375, 400–404 ( 1995).

    Article  CAS  Google Scholar 

  8. Isaac, J. T., Nicoll, R. A. & Malenka, R. C. Evidence for silent synapses: implications for the expression of LTP. Neuron 15, 427– 434 (1995).

    Article  CAS  Google Scholar 

  9. Mayer, M. L., Westbrook, G. L. & Guthrie, P. B. Voltage–dependent block by Mg2+ of NMDA responses in spinal cord neurons. Nature 309 , 261–263 (1984).

    Article  CAS  Google Scholar 

  10. Rusakov, D. A. & Kullmann, D. M. Extrasynaptic glutamate diffusion in the hippocampus: ultrastructural constraints, uptake, and receptor activation. J. Neurosci. 18, 3158–3170 (1998).

    Article  CAS  Google Scholar 

  11. Kullmann, D. M. & Asztely, F. Extrasynaptic glutamate spillover in the hippocampus: evidence and implications. Trends Neurosci. 21, 8–14 (1998).

    Article  CAS  Google Scholar 

  12. Dong, H. et al. GRIP: a synaptic PDZ domain–containing protein that interacts with AMPA receptors. Nature 386, 279– 284 (1997).

    Article  CAS  Google Scholar 

  13. Barria, A., Muller, D., Derkach, V., Griffith, L. C. & Soderling, T. R. Regulatory phosphorylation of AMPA–type glutamate receptors by CaM–KII during long–term potentiation. Science 276, 2042–2045 ( 1997).

    Article  CAS  Google Scholar 

  14. Kharazia, V. N., Phend, K. D., Rustioni, A. & Weinberg, R. J. EM colocalization of AMPA and NMDA receptor subunits at synapses in rat cerebral cortex. Neurosci. Lett. 210, 37– 40 (1996).

    Article  CAS  Google Scholar 

  15. Desmond, N. L. & Weinberg, R. J. Enhanced expression of AMPA receptor protein at perforated axospinous synapses. Neuroreport 9, 857–860 ( 1998).

    Article  CAS  Google Scholar 

  16. Wenthold, R. J., Petralia, R. S., Blahos, J. II & Niedzielski, A. S. Evidence for multiple AMPA receptor complexes in hippocampal CA1/CA2 neurons. J. Neurosci. 16, 1982–1989 (1996).

    Article  CAS  Google Scholar 

  17. Bekkers, J. M., Richerson, G. B. & Stevens, C. F. Origin of variability in quantal size in cultured hippocampal neurons and hippocampal slices. Proc. Natl. Acad. Sci. USA 87, 5359–5362 ( 1990).

    Article  CAS  Google Scholar 

  18. Shatz, C. J. Impulse activity and the patterning of connections during CNS development. Neuron 5, 745–756 (1990).

    Article  CAS  Google Scholar 

  19. Fox, K. The critical period for long–term potentiation in primary sensory cortex. Neuron 15, 485–488 (1995).

    Article  CAS  Google Scholar 

  20. Katz, L. C. & Shatz, C. J. Synaptic activity and the construction of cortical circuits. Science 274, 1132– 1138 (1996).

    Article  Google Scholar 

  21. Constantine–Paton, M. & Cline, H. T. LTP and activity–dependent synaptogenesis: the more alike they are, the more different they become. Curr. Opin. Neurobiol. 8, 139–148 (1998).

    Article  Google Scholar 

  22. Wang, Y.–X., Wenthold, R. J., Ottersen, O. P. & Petralia, R. S. Endbulb synapses in the anteroventral cochlear nucleus express a specific subset of AMPA–type glutamate receptor subunits. J. Neurosci. 18, 1148–1160 ( 1998).

    Article  CAS  Google Scholar 

  23. Zhao, H.–M., Wenthold, R. J. & Petralia, R. S. Glutamate receptor targeting to synaptic populations on Purkinje cells is developmentally regulated. J. Neurosci. 18, 5517–5528 (1998).

    Article  CAS  Google Scholar 

  24. Matsubara, A., Laake, J. H., Davanger, S., Usami, S. & Ottersen, O. P. Organization of AMPA receptor subunits at a glutamate synapse: a quantitative immunogold analysis of hair cell synapses in the rat organ of Corti. J. Neurosci. 16, 4457–4467 (1996).

    Article  CAS  Google Scholar 

  25. Wang, B.–L. & Larsson, L.–I. Simultaneous demonstration of multiple antigens by indirect immunofluorescence or immunogold staining. Novel light and electron microscopical double and triple staining method employing primary antibodies from the same species. Histochemistry 83, 47–56 ( 1985).

    Article  CAS  Google Scholar 

  26. Wenthold, R. J., Yokotani, N., Doi, K. & Wada, K. Immunochemical characterization of the non–NMDA glutamate receptor using subunit–specific antibodies. Evidence for a hetero–oligomeric structure in rat brain. J. Biol. Chem. 267, 501–507 (1992).

    CAS  Google Scholar 

  27. Petralia, R. S. & Wenthold, R. J. Light and electron immunocytochemical localization of AMPA–selective glutamate receptors in the rat brain. J. Comp. Neurol. 318, 329–354 (1992).

    Article  CAS  Google Scholar 

  28. Petralia, R. S., Yokotani, N. & Wenthold, R. J. Light and electron microscope distribution of the NMDA receptor subunit NMDAR1 in the rat nervous system using a selective anti–peptide antibody. J. Neurosci. 14, 667– 696 (1994).

    Article  CAS  Google Scholar 

  29. Petralia, R. S., Wang, Y.–X. & Wenthold, R. J. The NMDA receptor subunits NR2A and NR2B show histological and ultrastructural localization patterns similar to those of NR1. J. Neurosci. 14, 6102–6120 (1994).

    Article  CAS  Google Scholar 

  30. Petralia, R. S., Wang, Y.–X., Mayat, E. & Wenthold, R. J. Glutamate receptor subunit 2–selective antibody shows a differential distribution of calcium–impermeable AMPA receptors among populations of neurons. J. Comp. Neurol. 385, 456– 476 (1997).

    Article  CAS  Google Scholar 

  31. Johnson, M. L. & Faunt, L. M. Parameter estimation by least–squares methods. Methods Enzymol. 210 , 1–37 (1992).

    Article  CAS  Google Scholar 

  32. Straume, M. & Johnson, M. L. Monte Carlo method for determining complete confidence probability distributions of estimated model parameters. Methods Enzymol. 210, 117– 129 (1992).

    Article  CAS  Google Scholar 

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We thank A. Allen and N. Dawkins–Pisani for technical support, and J. Lisman and members of the Malinow and Wenthold laboratories for comments.

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Correspondence to R. Malinow.

Supplementary information

Supplementary Figure

Low-detection analysis of theoretical receptor frequency distributions. (a) Comparison of goodness-of-fit with Poisson or gamma distributions. Theoretical distributions were composed of 500 synapses. For half of the synapses (250), the number of receptors in each synapse was determined randomly according to a gamma distribution with mean of 30 receptors/synapse and different coefficients of variation (c.v.) as indicated. (Similar conclusions were obtained with other theoretical distributions: binomial, bimodal and uniform.) The remaining 50% of the synapses were considered to have no receptor, that is, FLR = 0.5. These distributions were randomly sampled with a detection efficiency of 0.1 (Methods). Then, the resulting distributions were fitted to a model comprised of a Poisson distribution plus a fraction of zeroes (filled bars) or a gamma distribution plus a fraction of zeroes (open bars). The goodness-of-fit was evaluated by comparing the corresponding cumulative distributions according to the Kolmogorov-Smirnov test. Significance levels obtained for each model are plotted as a function of the c.v. of the original, non-zero, distribution. Notice that the model composed of a Poisson distribution plus a fraction of zeroes fails to describe accurately (has low goodness of fit) low-detection distributions that originated from broad receptor distributions (c.v. = 0.6). Nevertheless, a good fit can be obtained even for very broad distributions (c.v. = 0.9) with a model composed of a gamma distribution plus a fraction of zeroes. (b) Effect of detection level and c.v. on the estimated fraction of synapses lacking receptors (FLR) and the goodness of fit. Two groups of theoretical distributions with the indicated c.v. were generated as described above. One group included 50% of synapses lacking receptors (FLR = 0.5, filled symbols), whereas in the other group all synapses contained receptors (FLR = 0, open symbols). Each theoretical distribution was randomly sampled with different detection efficiencies (Methods). Then, the resulting distributions were fitted to a Poisson distribution plus a fraction of zeroes (FLR). Average values of FLR are plotted as a function of the detection level, error bars representing one standard deviation. The correct values for FLR (either 0 or 0.5) are indicated with dashed lines. The goodness-of-fit was evaluated by comparing the corresponding cumulative distributions according to the Kolmogorov-Smirnov test. The significance levels (p) obtained for each distribution sampled at 0.1 detection are indicated (p = 1.00 for lower detection values). Notice how the estimated value for FLR increases above its real value (either 0 or 0.5) when detection becomes smaller and c.v. is large. This effect is more pronounced when the starting distribution has a low FLR value (0 versus 0.5). Nevertheless, the estimations were always accurate (close to the actual value of FLR) when they showed no dependence on the detection level. Therefore, a plot of FLR estimation versus detection can be used as a diagnostic method for the accuracy of the estimated values. (GIF 25 kb)

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Petralia, R., Esteban, J., Wang, Y. et al. Selective acquisition of AMPA receptors over postnatal development suggests a molecular basis for silent synapses. Nat Neurosci 2, 31–36 (1999).

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