Estimating the Distribution of Synaptic Reliabilities

• Published in: Journal of neurophysiology Vol. 78; no. 6; pp. 2870 - 2880
• Main Authors: Huang, Emily P, Stevens, Charles F
• Format: Journal Article
• Language: English
• Published: United States Am Phys Soc 01.12.1997
• Subjects: Animals; Dizocilpine Maleate - pharmacology; Excitatory Amino Acid Antagonists - pharmacology; Excitatory Postsynaptic Potentials; In Vitro Techniques; Linear Models; Probability; Pyramidal Cells - drug effects; Pyramidal Cells - physiology; Rats; Receptors, N-Methyl-D-Aspartate - antagonists & inhibitors; Receptors, N-Methyl-D-Aspartate - physiology; Reproducibility of Results; Synapses - physiology
• ISSN: 0022-3077; 1522-1598
• DOI: 10.1152/jn.1997.78.6.2870

Emily P. Huang 1 and Charles F. Stevens 2 1  Neuroscience Department, University of California San Diego, La Jolla 92093; and 2  Howard Hughes Medical Institute, The Salk Institute, La Jolla, California 92037 Huang, Emily P. and Charles F. Stevens. Estimating the distribution of synaptic reliabilities. J. Neurophysiol. 78: 2870-2880, 1997. Using whole cell recording from CA1 hippocampal pyramidal neurons in slices, we examined the progressive decrease of N -methyl- D -aspartate receptor-mediated synaptic responses in the presence of the open-channel blocker MK-801. Previous studies analyzing this decrease have proposed that hippocampal synapses fall into two distinct classes of release probabilities, whereas studies based on other methods indicate a broad distribution of synaptic reliabilities exists. Here we derive the theoretical relationship between the MK-801-mediated decrease in excitatory postsynaptic current amplitudes and the underlying distribution of synaptic reliabilities. We find that the MK-801 data are consistent with a continuous distribution of synaptic reliabilities, in agreement with studies examining individual synapses. In addition, changes in the MK-801-mediated decrease in response size as a consequence of altering release probability are consistent with this continuous distribution of synaptic reliabilities.