Synaptic calcium transients in single spines indicate that NMDA receptors are not saturated

Mainen, Z. F., Malinow, R., Svoboda, K. (1999) Synaptic calcium transients in single spines indicate that NMDA receptors are not saturated. Nature, 399 (6732). pp. 151-5. ISSN 0028-0836 (Print)

URL: http://www.ncbi.nlm.nih.gov/pubmed/10335844
DOI: 10.1038/20187

Abstract

At excitatory synapses in the central nervous system, the number of glutamate molecules released from a vesicle is much larger than the number of postsynaptic receptors. But does release of a single vesicle normally saturate these receptors? Answering this question is critical to understanding how the amplitude and variability of synaptic transmission are set and regulated. Here we describe the use of two-photon microscopy to image transient increases in Ca2+ concentration mediated by NMDA (N-methyl-D-aspartate) receptors in single dendritic spines of CA1 pyramidal neurons in hippocampal slices. To test for NMDA-receptor saturation, we compared responses to stimulation with single and double pulses. We find that a single release event does not saturate spine NMDA receptors; a second release occurring 10 ms later produces approximately 80% more NMDA-receptor activation. The amplitude of spine NMDA-receptor-mediated [Ca2+] transients (and the synaptic plasticity which depends on this) may thus be sensitive to the number of quanta released by a burst of action potentials and to changes in the concentration profile of glutamate in the synaptic cleft.

Item Type: Paper
Uncontrolled Keywords: Action Potentials Animals Calcium/ metabolism Dendrites/ metabolism Glutamic Acid/metabolism Hippocampus/cytology/physiology In Vitro Microscopy, Confocal N-Methylaspartate/metabolism Neuronal Plasticity/physiology Neurons/metabolism/physiology Rats Receptors, N-Methyl-D-Aspartate/ metabolism Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, P.H.S. Synapses/ physiology
Subjects: bioinformatics > genomics and proteomics > small molecules > NMDA receptor
organs, tissues, organelles, cell types and functions > tissues types and functions > hippocampus
Investigative techniques and equipment > microscopy
organs, tissues, organelles, cell types and functions > cell types and functions > cell types > neurons
organs, tissues, organelles, cell types and functions > cell types and functions > cell types > neurons
organs, tissues, organelles, cell types and functions > cell types and functions > cell types > neurons

organs, tissues, organelles, cell types and functions > sub-cellular tissues: types and functions > synapse
CSHL Authors:
Communities: CSHL labs > Mainen lab
CSHL labs > Malinow lab
CSHL labs > Svoboda lab
Depositing User: Kathleen Darby
Date Deposited: 28 Apr 2014 16:44
Last Modified: 28 Apr 2014 16:44
Related URLs:
URI: http://repository.cshl.edu/id/eprint/29818

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