Synaptic refractory period provides a measure of probability of release in the hippocampus.
Despite extensive research, much controversy remains regarding the locus of expression of long-term potentiation (LTP) in area CA1 of the hippocampus, specifically, whether LTP is accompanied by an increase in the probability of release (p(r)) of synaptic vesicles. We have developed a novel method for assaying p(r), which utilizes the synaptic refractory period--a brief 5-6 ms period following release during which the synapse is incapable of transmission (Stevens and Wang, 1995). We show that this assay is sensitive to a battery of manipulations that affect p(r) but find no change following either NMDA receptor-dependent LTP or long-term depression (LTD).
Hjelmstad
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GO
Neuroscience Graduate Program, University of California, San Francisco 94143, USA.
Nicoll
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RA
Malenka
R C
RC
D000818:Animals; D005071:Evoked Potentials / Q000502:physiology*; D006624:Hippocampus / Q000502:physiology*; D066298:In Vitro Techniques; D017774:Long-Term Potentiation / Q000502:physiology*; D008959:Models, Neurological; D009474:Neurons / Q000502:physiology*; D011336:Probability; D051381:Rats; D017207:Rats, Sprague-Dawley; D013569:Synapses / Q000502:physiology*; D013572:Synaptic Vesicles / Q000502:physiology*