Very Short-Term Plasticity in Hippocampal Synapses

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 94; no. 26; pp. 14843 - 14847
• Main Authors: Dobrunz, L E, Huang, E P, Stevens, C F
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences of the United States of America 23.12.1997; National Acad Sciences; National Academy of Sciences; The National Academy of Sciences of the USA
• Subjects: Action potentials; Animal behavior; Animals; Biological Sciences; Brain; Calcium; Hippocampus - physiology; Histograms; Mental stimulation; Neurobiology; Neurology; Neuronal Plasticity - physiology; Neurons; Neurotransmitters; Ratios; Rats; Rodents; Synapses; Synapses - physiology; Time constants; Time Factors
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.94.26.14843

Hippocampal pyramidal neurons often fire in bursts of action potentials with short interspike intervals (2-10 msec). These high-frequency bursts may play a critical role in the functional behavior of hippocampal neurons, but synaptic plasticity at such short times has not been carefully studied. To study synaptic modulation at very short time intervals, we applied pairs of stimuli with interpulse intervals ranging from 7 to 50 msec to CA1 synapses isolated by the method of minimal stimulation in hippocampal slices. We have identified three components of short-term paired-pulse modulation, including (i) a form of synaptic depression manifested after a prior exocytotic event, (ii) a form of synaptic depression that does not depend on a prior exocytotic event and that we postulate is based on inactivation of presynaptic N-type Ca2+channels, and (iii) a dependence of paired-pulse facilitation on the exocytotic history of the synapse.