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Logo of jphysiolThe Journal of Physiology SiteMembershipSubmissionJ Physiol
J Physiol. 1982; 324: 249–262.
PMCID: PMC1250703

Long-term synaptic enhancement and short-term potentiation in rat fascia dentata act through different mechanisms

Abstract

1. The component processes contributing to post-activation change in synaptic efficacy in the perforant pathway to the fascia dentata were studied in rats under sodium pentobarbitone anaesthesia.

2. With low stimulus strength, which activated only a relatively small number of perforant path fibres, repetitive stimulation led to effects which had very similar characteristics to those observed at neuromuscular synapses under similar conditions. Paired shocks resulted in a short (~ 100 ms) facilitation superimposed on a depression, possibly due to depletion of available transmitter, which recovered more slowly (~ 4 s). Short trains of stimuli at 125-250 Hz led to a longer lasting increase in synaptic strength which decayed to control levels with a double exponential time course. The two exponential components behaved like augmentation and potentiation at neuromuscular synapses, with time constants at 33 °C of about 5 s and about 90 s respectively.

3. High-intensity stimulus trains of identical frequency and duration led to an enhancement of synaptic strength which lasted for longer than 30 min.

4. The paired shock depletion effect was increased in direct proportion to the amount of augmentation and potentiation present following low-intensity stimulus trains. Following high-intensity trains the paired shock depletion effect was increased by the same amount, and recovered with the same time course as following low-intensity stimulus trains, even though there remained a significant enhancement of the synaptic response.

5. The results are interpreted as indicating that augmentation and potentiation are due to an increase in the probability of transmitter release whereas long-term enhancement acts through some other, as yet undetermined, mechanism. Following high-intensity stimulation all three processes are activated.

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Selected References

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  • Andersen P, Holmqvist B, Voorhoeve PE. Entorhinal activation of dentate granule cells. Acta Physiol Scand. 1966 Apr;66(4):448–460. [PubMed]
  • Betz WJ. Depression of transmitter release at the neuromuscular junction of the frog. J Physiol. 1970 Mar;206(3):629–644. [PMC free article] [PubMed]
  • Bliss TV, Gardner-Medwin AR. Long-lasting potentiation of synaptic transmission in the dentate area of the unanaestetized rabbit following stimulation of the perforant path. J Physiol. 1973 Jul;232(2):357–374. [PMC free article] [PubMed]
  • Bliss TV, Lomo T. Long-lasting potentiation of synaptic transmission in the dentate area of the anaesthetized rabbit following stimulation of the perforant path. J Physiol. 1973 Jul;232(2):331–356. [PMC free article] [PubMed]
  • Christensen BN, Martin AR. Estimates of probability of transmitter release at the mammalian neuromuscular junction. J Physiol. 1970 Nov;210(4):933–945. [PMC free article] [PubMed]
  • DEL CASTILLO J, KATZ B. Statistical factors involved in neuromuscular facilitation and depression. J Physiol. 1954 Jun 28;124(3):574–585. [PMC free article] [PubMed]
  • Douglas RM, Goddard GV. Long-term potentiation of the perforant path-granule cell synapse in the rat hippocampus. Brain Res. 1975 Mar 21;86(2):205–215. [PubMed]
  • GLOOR P, VERA CL, SPERTI L. ELECTROPHYSIOLOGICAL STUDIES OF HIPPOCAMPAL NEURONS. 3. RESPONSES OF HIPPOCAMPAL NEURONS TO REPETITIVE PERFORANT PATH VOLLEYS. Electroencephalogr Clin Neurophysiol. 1964 Oct;17:353–370. [PubMed]
  • Landau EM, Smolinsky A, Lass Y. Post-tetanic potentiation and facilitation do not share a common calcium-dependent mechanism. Nat New Biol. 1973 Aug 1;244(135):155–157. [PubMed]
  • LILEY AW. An investigation of spontaneous activity at the neuromuscular junction of the rat. J Physiol. 1956 Jun 28;132(3):650–666. [PMC free article] [PubMed]
  • LILEY AW, NORTH KA. An electrical investigation of effects of repetitive stimulation on mammalian neuromuscular junction. J Neurophysiol. 1953 Sep;16(5):509–527. [PubMed]
  • LLOYD DPC. Post-tetanic potentiation of response in monosynaptic reflex pathways of the spinal cord. J Gen Physiol. 1949 Nov;33(2):147–170. [PMC free article] [PubMed]
  • Lomo T. Potentiation of monosynaptic EPSPs in the perforant path-dentate granule cell synapse. Exp Brain Res. 1971;12(1):46–63. [PubMed]
  • McNaughton BL. Evidence for two physiologically distinct perforant pathways to the fascia dentata. Brain Res. 1980 Oct 13;199(1):1–19. [PubMed]
  • McNaughton BL, Barnes CA. Physiological identification and analysis of dentate granule cell responses to stimulation of the medial and lateral perforant pathways in the rat. J Comp Neurol. 1977 Oct 15;175(4):439–454. [PubMed]
  • McNaughton BL, Douglas RM, Goddard GV. Synaptic enhancement in fascia dentata: cooperativity among coactive afferents. Brain Res. 1978 Nov 24;157(2):277–293. [PubMed]
  • Magleby KL. The effect of tetanic and post-tetanic potentiation on facilitation of transmitter release at the frog neuromuscular junction. J Physiol. 1973 Oct;234(2):353–371. [PMC free article] [PubMed]
  • Magleby KL, Zengel JE. A quantitative description of tetanic and post-tetanic potentiation of transmitter release at the frog neuromuscular junction. J Physiol. 1975 Feb;245(1):183–208. [PMC free article] [PubMed]
  • Magleby KL, Zengel JE. Augmentation: A process that acts to increase transmitter release at the frog neuromuscular junction. J Physiol. 1976 May;257(2):449–470. [PMC free article] [PubMed]
  • Magleby KL, Zengel JE. Long term changes in augmentation, potentiation, and depression of transmitter release as a function of repeated synaptic activity at the frog neuromuscular junction. J Physiol. 1976 May;257(2):471–494. [PMC free article] [PubMed]
  • MARTIN AR, PILAR G. PRESYNAPTIC AND POST-SYNAPTIC EVENTS DURING POST-TETANIC POTENTIATION AND FACILITATION IN THE AVIAN CILIARY GANGLION. J Physiol. 1964 Dec;175:17–30. [PMC free article] [PubMed]
  • OTSUKA M, ENDO M, NONOMURA Y. Presynaptic nature of neuromuscular depression. Jpn J Physiol. 1962 Dec 15;12:573–584. [PubMed]
  • Rosenthal J. Post-tetanic potentiation at the neuromuscular junction of the frog. J Physiol. 1969 Jul;203(1):121–133. [PMC free article] [PubMed]
  • TAKEUCHI A. The long-lasting depression in neuromuscular transmission of frog. Jpn J Physiol. 1958 Jun 15;8(2):102–113. [PubMed]
  • Weinreich D. Ionic mechanism of post-tetanic potentiation at the neuromuscular junction of the frog. J Physiol. 1971 Jan;212(2):431–446. [PMC free article] [PubMed]

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