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. 1982 Sep;79(17):5430–5434. doi: 10.1073/pnas.79.17.5430

Post-tetanic potentiation at an identified synapse in Aplysia is correlated with a Ca2+-activated K+ current in the presynaptic neuron: evidence for Ca2+ accumulation.

R Kretz, E Shapiro, E R Kandel
PMCID: PMC346911  PMID: 6291044

Abstract

We have examined the presynaptic changes underlying post-tetanic potentiation (PTP) in Aplysia by using voltage-clamp techniques combined with specific pharmacological blocking agents. The amplitude and time course of PTP parallel a slow outward clamp current that we have identified as a Ca2+-activated K+ current. Because this current is proportional to intracellular Ca2+ concentration our findings provide evidence for the "residual Ca2+ hypothesis," according to which PTP is caused by the accumulation of intracellular Ca2+ after tetanus. To obtain further evidence for this mechanism we injected EGTA intracellularly and found that it decreased the duration of both PTP and the Ca2+ -activated K+ current.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Adams D. J., Smith S. J., Thompson S. H. Ionic currents in molluscan soma. Annu Rev Neurosci. 1980;3:141–167. doi: 10.1146/annurev.ne.03.030180.001041. [DOI] [PubMed] [Google Scholar]
  2. Byrne J. H., Shapiro E., Dieringer N., Koester J. Biophysical mechanisms contributing to inking behavior in Aplysia. J Neurophysiol. 1979 Sep;42(5):1233–1250. doi: 10.1152/jn.1979.42.5.1233. [DOI] [PubMed] [Google Scholar]
  3. Connor J. A. Calcium current in molluscan neurones: measurement under conditions which maximize its visibility. J Physiol. 1979 Jan;286:41–60. doi: 10.1113/jphysiol.1979.sp012606. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Erulkar S. D., Rahamimoff R. The role of calcium ions in tetanic and post-tetanic increase of miniature end-plate potential frequency. J Physiol. 1978 May;278:501–511. doi: 10.1113/jphysiol.1978.sp012320. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Gage P. W., Hubbard J. I. An investigation of the post-tetanic potentiation of end-plate potentials at a mammalian neuromuscular junction. J Physiol. 1966 May;184(2):353–375. doi: 10.1113/jphysiol.1966.sp007919. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Gorman A. L., Hermann A. Internal effects of divalent cations on potassium permeability in molluscan neurones. J Physiol. 1979 Nov;296:393–410. doi: 10.1113/jphysiol.1979.sp013012. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. KATZ B., MILEDI R. THE EFFECT OF CALCIUM ON ACETYLCHOLINE RELEASE FROM MOTOR NERVE TERMINALS. Proc R Soc Lond B Biol Sci. 1965 Feb 16;161:496–503. doi: 10.1098/rspb.1965.0017. [DOI] [PubMed] [Google Scholar]
  8. Katz B., Miledi R. The role of calcium in neuromuscular facilitation. J Physiol. 1968 Mar;195(2):481–492. doi: 10.1113/jphysiol.1968.sp008469. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Klein M., Kandel E. R. Presynaptic modulation of voltage-dependent Ca2+ current: mechanism for behavioral sensitization in Aplysia californica. Proc Natl Acad Sci U S A. 1978 Jul;75(7):3512–3516. doi: 10.1073/pnas.75.7.3512. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. LLOYD D. P. C. Post-tetanic potentiation of response in monosynaptic reflex pathways of the spinal cord. J Gen Physiol. 1949 Nov;33(2):147–170. doi: 10.1085/jgp.33.2.147. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Magleby K. L., Zengel J. E. Augmentation: A process that acts to increase transmitter release at the frog neuromuscular junction. J Physiol. 1976 May;257(2):449–470. doi: 10.1113/jphysiol.1976.sp011378. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Marty A. Ca-dependent K channels with large unitary conductance in chromaffin cell membranes. Nature. 1981 Jun 11;291(5815):497–500. doi: 10.1038/291497a0. [DOI] [PubMed] [Google Scholar]
  13. Meech R. W. Calcium-dependent potassium activation in nervous tissues. Annu Rev Biophys Bioeng. 1978;7:1–18. doi: 10.1146/annurev.bb.07.060178.000245. [DOI] [PubMed] [Google Scholar]
  14. Meech R. W. Intracellular calcium injection causes increased potassium conductance in Aplysia nerve cells. Comp Biochem Physiol A Comp Physiol. 1972 Jun 1;42(2):493–499. doi: 10.1016/0300-9629(72)90128-4. [DOI] [PubMed] [Google Scholar]
  15. Pallotta B. S., Magleby K. L., Barrett J. N. Single channel recordings of Ca2+-activated K+ currents in rat muscle cell culture. Nature. 1981 Oct 8;293(5832):471–474. doi: 10.1038/293471a0. [DOI] [PubMed] [Google Scholar]
  16. Partridge L. D., Stevens C. F. A mechanism for spike frequency adaptation. J Physiol. 1976 Apr;256(2):315–332. doi: 10.1113/jphysiol.1976.sp011327. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Rahamimoff R. A dual effect of calcium ions on neuromuscular facilitation. J Physiol. 1968 Mar;195(2):471–480. doi: 10.1113/jphysiol.1968.sp008468. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Rosenthal J. Post-tetanic potentiation at the neuromuscular junction of the frog. J Physiol. 1969 Jul;203(1):121–133. doi: 10.1113/jphysiol.1969.sp008854. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Schlapfer W. T., Tremblay J. P., Woodson P. B., Barondes S. H. Frequency facilitation and post-tetanic potentiation of a unitary synaptic potential in Aplysia californica are limited by different processes. Brain Res. 1976 Jun 4;109(1):1–20. doi: 10.1016/0006-8993(76)90377-2. [DOI] [PubMed] [Google Scholar]
  20. Shapiro E., Castellucci V. F., Kandel E. R. Presynaptic inhibition in Aplysia involves a decrease in the Ca2+ current of the presynaptic neuron. Proc Natl Acad Sci U S A. 1980 Feb;77(2):1185–1189. doi: 10.1073/pnas.77.2.1185. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Shapiro E., Castellucci V. F., Kandel E. R. Presynaptic membrane potential affects transmitter release in an identified neuron in Aplysia by modulating the Ca2+ and K+ currents. Proc Natl Acad Sci U S A. 1980 Jan;77(1):629–633. doi: 10.1073/pnas.77.1.629. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Tillotson D. Inactivation of Ca conductance dependent on entry of Ca ions in molluscan neurons. Proc Natl Acad Sci U S A. 1979 Mar;76(3):1497–1500. doi: 10.1073/pnas.76.3.1497. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Waziri R., Kandel E. R., Frazier W. T. Organization of inhibition in abdominal ganglion of Aplysia. II. Posttetanic potentiation, heterosynaptic depression, and increments in frequency of inhibitory postsynaptic potentials. J Neurophysiol. 1969 Jul;32(4):509–519. doi: 10.1152/jn.1969.32.4.509. [DOI] [PubMed] [Google Scholar]
  24. Waziri R. Presynaptic electrical coupling in Aplysia: effects on postsynaptic chemical transmission. Science. 1977 Feb 25;195(4280):790–792. doi: 10.1126/science.189390. [DOI] [PubMed] [Google Scholar]
  25. Weinreich D. Ionic mechanism of post-tetanic potentiation at the neuromuscular junction of the frog. J Physiol. 1971 Jan;212(2):431–446. doi: 10.1113/jphysiol.1971.sp009333. [DOI] [PMC free article] [PubMed] [Google Scholar]

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