Summary
The values of quantal content (m) and quantal amplitude (q) of excitatory postsynaptic potentials (EPSPs) elicited in CA3 neurons by activation of granule cells were estimated in thin hippocampal sections maintained in vitro. For this purpose, DL-homocysteate was administered to granule cells, and trains of EPSPs that were typical for single granule cell activation were recorded from individual CA3 neurons. The amplitudes of the first and second EPSPs in each train were measured. From the mean and variance of the amplitudes of the EPSPs, the values of q and m were calculated. The values of m and q for the first EPSPs were estimated at 8.3 and 0.28 mV, respectively, on the average. Potentiation of the second EPSPs was accompanied by a two-fold increase in the values of m without changes in the values of q. Therefore, frequency potentiation in synapses between mossy fibers and CA3 neurons may be explained by an increase in number of released quanta. Amplitudes of EPSPs were found to fluctuate in a manner described by Poisson's law.
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References
Brown TH, Wong RKS, Prince DA (1979) Spontaneous miniature synaptic potentials in hippocampal neurons. Brain Res 177: 194–199
Del Castillo J, Katz B (1954) Statistical factors involved in neuromuscular facilitation and depression. J Physiol (Lond) 124: 574–585
Hamlyn LH (1962) The fine structure of the mossy fiber endings in the hippocampus of the rabbit. J Anat (Lond) 96: 112–120
Hubbard JI, Llinás R, Quastel DMJ (1969) Electrophysiological analysis of synaptic transmission. Arnold, London
Katz B (1966) Nerve, muscle, and synapse. McGraw-Hill, New York
Kuno M (1964a) Quantal components of excitatory synaptic potentials in spinal motoneurones. J Physiol (Lond) 175: 81–99
Kuno M (1964b) Mechanism of facilitation and depression of the excitatory synaptic potential in spinal motoneurones. J Physiol (Lond) 175: 100–112
Kuno M, Monoz-Martinez EJ, Randic M (1973) Synaptic action on Clarke's column neurones in relation to afferent terminal size. J Physiol (Lond) 228: 343–360
Kuno M, Turkanis SA, Weakly JN (1971) Correlation between nerve terminal size and transmitter release at the neuromuscular junction of the frog. J Physiol (Lond) 213: 545–556
Kuno M, Weakly JN (1972) Facilitation of monosynaptic excitatory synaptic potentials in spinal motoneurones evoked by internuncial impulses. J Physiol (Lond) 224: 271–286
Martin AR (1955) A further study of the statistical composition of the end-plate potential. J Physiol (Lond) 130: 114–122
Martin AR (1977) Junctional transmission. II. Presynaptic mechanisms. In: Kandel ER (ed) Handbook of physiology, sect 1, vol 1. American Physiological Society, Bethesda, pp 329–355
Spencer WA, Kandel ER (1961) Electrophysiology of hippocampal neurones. IV. Fast prepotentials. J Neurophysiol 24: 272–285
Yamamoto C (1972) Activation of hippocampal neurons by mossy fiber stimulation in thin brain sections in vitro. Exp Brain Res 14: 423–435
Yamamoto C, Matsumoto K, Takagi M (1980) Potentiation of excitatory postsynaptic potentials during and after repetitive stimulation in thin hippocampal sections. Exp Brain Res 38: 469–477
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Supported by a grant from the Ministry of Education of Japan
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Yamamoto, C. Quantal analysis of excitatory postsynaptic potentials induced in hippocampal neurons by activation of granule cells. Exp Brain Res 46, 170–176 (1982). https://doi.org/10.1007/BF00237173
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DOI: https://doi.org/10.1007/BF00237173