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. 1984 Sep;83(1):31–42. doi: 10.1111/j.1476-5381.1984.tb10116.x

Alteration of the fast excitatory postsynaptic current by barium in voltage-clamped amphibian sympathetic ganglion cells.

E A Connor, R L Parsons
PMCID: PMC1987177  PMID: 6333261

Abstract

Barium-induced alterations in fast excitatory postsynaptic currents (e.p.s.cs) have been studied in voltage-clamped bullfrog sympathetic ganglion B cells. In the presence of 2-8 mM barium, e.p.s.c. decay was prolonged and in many cells the e.p.s.c. decay phase deviated from a single exponential function. The decay phase in these cases was more accurately described as the sum of two exponential functions. The frequency of occurrence of a complex decay increased both with increasing barium concentration and with hyperpolarization. Miniature e.p.s.c. decay also was prolonged in barium-treated cells. E.p.s.c. amplitude was not markedly affected by barium (2-8 mM) in cells voltage-clamped to -50 mV whereas at -90 mV there was a progressive increase in peak size with increasing barium concentration. In control cells the e.p.s.c.-voltage relationship was linear between -20 and -100 mV; however, this relationship became progressively non-linear with membrane hyperpolarization in barium-treated cells. The e.p.s.c. reversal potential was shifted to a more negative value in the presence of barium. There was a voltage-dependent increase in charge movement during the e.p.s.c. in barium-treated cells which was not present in control cells. We conclude that the voltage-dependent alteration in e.p.s.c. decay time course, peak amplitude and charge movement in barium-treated cells is due to a direct postsynaptic action of barium on the kinetics of receptor-channel gating in postganglionic sympathetic neurones.

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Selected References

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  1. Adams D. J., Dwyer T. M., Hille B. The permeability of endplate channels to monovalent and divalent metal cations. J Gen Physiol. 1980 May;75(5):493–510. doi: 10.1085/jgp.75.5.493. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Adams P. R., Brown D. A., Constanti A. Pharmacological inhibition of the M-current. J Physiol. 1982 Nov;332:223–262. doi: 10.1113/jphysiol.1982.sp014411. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Adams P. R. Drug blockade of open end-plate channels. J Physiol. 1976 Sep;260(3):531–552. doi: 10.1113/jphysiol.1976.sp011530. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Armstrong C. M., Taylor S. R. Interaction of barium ions with potassium channels in squid giant axons. Biophys J. 1980 Jun;30(3):473–488. doi: 10.1016/S0006-3495(80)85108-3. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. BLACKMAN J. G., GINSBORG B. L., RAY C. Spontaneous synaptic activity in sympathetic ganglion cells of the frog. J Physiol. 1963 Jul;167:389–401. doi: 10.1113/jphysiol.1963.sp007157. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Bregestovski P. D., Miledi R., Parker I. Calcium conductance of acetylcholine-induced endplate channels. Nature. 1979 Jun 14;279(5714):638–639. doi: 10.1038/279638a0. [DOI] [PubMed] [Google Scholar]
  7. Connor E. A., Levy S. M., Parsons R. L. Kinetic analysis of atropine-induced alterations in bullfrog ganglionic fast synaptic currents. J Physiol. 1983 Apr;337:137–158. doi: 10.1113/jphysiol.1983.sp014616. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Connor E. A., Parsons R. L. Analysis of fast excitatory postsynaptic currents in bullfrog parasympathetic ganglion cells. J Neurosci. 1983 Nov;3(11):2164–2171. doi: 10.1523/JNEUROSCI.03-11-02164.1983. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Connor E. A., Parsons R. L. Procaine alters fast excitatory postsynaptic current decay in amphibian sympathetic ganglia. Br J Pharmacol. 1983 Feb;78(2):293–299. doi: 10.1111/j.1476-5381.1983.tb09394.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Dodd J., Horn J. P. A reclassification of B and C neurones in the ninth and tenth paravertebral sympathetic ganglia of the bullfrog. J Physiol. 1983 Jan;334:255–269. doi: 10.1113/jphysiol.1983.sp014493. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. 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]
  12. Hagiwara S., Byerly L. Calcium channel. Annu Rev Neurosci. 1981;4:69–125. doi: 10.1146/annurev.ne.04.030181.000441. [DOI] [PubMed] [Google Scholar]
  13. Hagiwara S., Ohmori H. Studies of calcium channels in rat clonal pituitary cells with patch electrode voltage clamp. J Physiol. 1982 Oct;331:231–252. doi: 10.1113/jphysiol.1982.sp014371. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Krnjević K., Pumain R., Renaud L. Effects of Ba2+ and tetraethylammonium on cortical neurones. J Physiol. 1971 May;215(1):223–245. doi: 10.1113/jphysiol.1971.sp009466. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Kuba K., Nishi S. Characteristics of fast excitatory postsynaptic current in bullfrog sympathetic ganglion cells. Effects of membrane potential, temperature and Ca ions. Pflugers Arch. 1979 Jan 31;378(3):205–212. doi: 10.1007/BF00592737. [DOI] [PubMed] [Google Scholar]
  16. Lewis C. A. Ion-concentration dependence of the reversal potential and the single channel conductance of ion channels at the frog neuromuscular junction. J Physiol. 1979 Jan;286:417–445. doi: 10.1113/jphysiol.1979.sp012629. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. MacDermott A. B., Connor E. A., Dionne V. E., Parsons R. L. Voltage clamp study of fast excitatory synaptic currents in bullfrog sympathetic ganglion cells. J Gen Physiol. 1980 Jan;75(1):39–60. doi: 10.1085/jgp.75.1.39. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Magleby K. L., Weinstock M. M. Nickel and calcium ions modify the characteristics of the acetylcholine receptor-channel complex at the frog neuromuscular junction. J Physiol. 1980 Feb;299:203–218. doi: 10.1113/jphysiol.1980.sp013120. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. McIsaac R. J. The influence of sodium, potassium and calcium on spontaneous miniature potentials in frog sympathetic ganglion neurons. Neuropharmacology. 1971 Sep;10(5):649–659. doi: 10.1016/0028-3908(71)90032-3. [DOI] [PubMed] [Google Scholar]
  20. McLachlan E. M. The effects of strontium and barium ions at synapses in sympathetic ganglia. J Physiol. 1977 May;267(2):497–518. doi: 10.1113/jphysiol.1977.sp011823. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Miledi R., Parker I. Effects of strontium ions on end-plate channel properties. J Physiol. 1980 Sep;306:567–577. doi: 10.1113/jphysiol.1980.sp013415. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Reuter H., Stevens C. F., Tsien R. W., Yellen G. Properties of single calcium channels in cardiac cell culture. Nature. 1982 Jun 10;297(5866):501–504. doi: 10.1038/297501a0. [DOI] [PubMed] [Google Scholar]
  23. Ruff R. L. A quantitative analysis of local anaesthetic alteration of miniature end-plate currents and end-plate current fluctuations. J Physiol. 1977 Jan;264(1):89–124. doi: 10.1113/jphysiol.1977.sp011659. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Ruff R. L. The kinetics of local anesthetic blockade of end-plate channels. Biophys J. 1982 Mar;37(3):625–631. [PMC free article] [PubMed] [Google Scholar]
  25. Schwindt P. C., Crill W. E. Effects of barium on cat spinal motoneurons studied by voltage clamp. J Neurophysiol. 1980 Oct;44(4):827–846. doi: 10.1152/jn.1980.44.4.827. [DOI] [PubMed] [Google Scholar]
  26. Silinsky E. M. Can barium support the release of acetylcholine by nerve impulses? Br J Pharmacol. 1977 Jan;59(1):215–217. doi: 10.1111/j.1476-5381.1977.tb06997.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  27. Sperelakis N., Schneider M. F., Harris E. J. Decreased K+ conductance produced by Ba++ in frog sartorius fibers. J Gen Physiol. 1967 Jul;50(6):1565–1583. doi: 10.1085/jgp.50.6.1565. [DOI] [PMC free article] [PubMed] [Google Scholar]
  28. Standen N. B., Stanfield P. R. A potential- and time-dependent blockade of inward rectification in frog skeletal muscle fibres by barium and strontium ions. J Physiol. 1978 Jul;280:169–191. doi: 10.1113/jphysiol.1978.sp012379. [DOI] [PMC free article] [PubMed] [Google Scholar]
  29. Takeda K., Gage P. W., Barry P. H. Effects of divalent cations on toad end-plate channels. J Membr Biol. 1982;64(1-2):55–66. doi: 10.1007/BF01870768. [DOI] [PubMed] [Google Scholar]
  30. Thesleff S. Aminopyridines and synaptic transmission. Neuroscience. 1980;5(8):1413–1419. doi: 10.1016/0306-4522(80)90002-0. [DOI] [PubMed] [Google Scholar]
  31. 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]

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