The probability of transmitter release at a mammalian central synapse

WHEN an action potential reaches a synaptic terminal, fusion of a transmitter-containing vesicle with the presynaptic membrane occurs with a probability ( p r ) of less than one 1 . Despite the fundamental importance of this parameter, p r has not been directly measured in the central nervous system...

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Bibliographic Details
Published in:Nature (London) 1993-12, Vol.366 (6455), p.569-572
Main Authors: Hessler, Neal A, Shirke, Aneil M, Malinow, Roberto
Format: Article
Language:English
Subjects:
Animals
Biological and medical sciences
Central nervous system
Central neurotransmission. Neuromudulation. Pathways and receptors
Dizocilpine Maleate - pharmacology
Electric Stimulation
Evoked Potentials - drug effects
Fundamental and applied biological sciences. Psychology
Hippocampus - physiology
Humanities and Social Sciences
In Vitro Techniques
Kinetics
letter
Mammals
Mathematics
Models, Neurological
multidisciplinary
Neurology
Neurons - drug effects
Neurons - physiology
Neurotransmitter Agents - metabolism
Neurotransmitter Agents - secretion
Probability
Pyramidal Tracts - physiology
Rats
Receptors, N-Methyl-D-Aspartate - drug effects
Receptors, N-Methyl-D-Aspartate - physiology
Science
Science (multidisciplinary)
Synapses - physiology
Vertebrates: nervous system and sense organs
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Description
Summary:WHEN an action potential reaches a synaptic terminal, fusion of a transmitter-containing vesicle with the presynaptic membrane occurs with a probability ( p r ) of less than one 1 . Despite the fundamental importance of this parameter, p r has not been directly measured in the central nervous system. Here we describe a novel approach to determine p r monitoring the decrement of NMDA ( N -methyl-D-aspartate)-receptor mediated synaptic currents in the presence of the use-dependent channel blocker MK-801 (ref. 2). On a single postsynaptic CA1 hippocampal slice neuron, two classes of synapses with a sixfold difference in p r are resolved. Synapses with low p r contribute to over half of transmission and are more sensitive to drugs enhancing transmitter release. Switching between these two classes of synapses provides the potential for large changes in synaptic efficacy and could underlie forms of activity-dependent plasticity.
ISSN:0028-0836
1476-4687
DOI:10.1038/366569a0