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. 1995 Jun 15;485(Pt 3):683–697. doi: 10.1113/jphysiol.1995.sp020762

The non-specific ion channel in Torpedo ocellata fused synaptic vesicles.

N Yakir 1, R Rahamimoff 1
PMCID: PMC1158037  PMID: 7562610

Abstract

1. Synaptic vesicles were isolated and fused into large structures with a diameter of more than 20 microns to characterize their ionic channels. The 'cell'-attached and inside-out configurations of the patch clamp technique were used. 2. Two types of ion channels were most frequently observed: a low conductance chloride channel and a high conductance non-specific channel. 3. The non-specific channel has a main conducting state and a substate. The main conducting state has a slope conductance of 246 +/- 15 pS (+/- S.E.M., n = 15), in the presence of different combinations of KCl and potassium glutamate. 4. From the reversal potentials of the current-voltage (I-V) relation, it was concluded that this channel conducts both Cl- and K+. 5. The non-specific channel is highly voltage dependent: under steady-state voltages it has a high open probability near 0 mV and does not inactivate; when the membrane is hyperpolarized (pipette side more positive), the open probability decreases dramatically. 6. Voltage pulses showed that upon hyperpolarization (from holding potentials between -20 and + 20 mV), the channels deactivated; when the membrane was stepped back to the holding potential, the channels reactivated rapidly. 7. In a number of experiments, when the pipette side was made more negative than the bath, the open probability also decreased. 8. Frequently, a substate with a conductance of about 44 +/- 4% (+/- S.E.M., n = 3) of the main state was detected. 9. We speculate that this non-specific ion channel may have different roles at the various stages of the life cycle of the synaptic vesicle. When the synaptic vesicle is an intracellular structure, it might help its transmitter-concentrating capacity by dissipating the polarization. After fusion with the surface membrane, it might constitute an additional conductance pathway, taking part in frequency modulation of synaptic transmission.

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Selected References

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  1. Angel I., Michaelson D. M. Determination of delta psi, delta pH and the proton electrochemical gradient in isolated cholinergic synaptic vesicles. Life Sci. 1981 Jul 27;29(4):411–416. doi: 10.1016/0024-3205(81)90335-0. [DOI] [PubMed] [Google Scholar]
  2. Arispe N., Pollard H. B., Rojas E. Calcium-independent K(+)-selective channel from chromaffin granule membranes. J Membr Biol. 1992 Nov;130(2):191–202. doi: 10.1007/BF00231896. [DOI] [PubMed] [Google Scholar]
  3. Bell J. E., Miller C. Effects of phospholipid surface charge on ion conduction in the K+ channel of sarcoplasmic reticulum. Biophys J. 1984 Jan;45(1):279–287. doi: 10.1016/S0006-3495(84)84154-5. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Bennett M. K., Scheller R. H. The molecular machinery for secretion is conserved from yeast to neurons. Proc Natl Acad Sci U S A. 1993 Apr 1;90(7):2559–2563. doi: 10.1073/pnas.90.7.2559. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Blatz A. L., Magleby K. L. Single voltage-dependent chloride-selective channels of large conductance in cultured rat muscle. Biophys J. 1983 Aug;43(2):237–241. doi: 10.1016/S0006-3495(83)84344-6. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Breer H., Morris S. J., Whittaker V. P. A structural model of cholinergic synaptic vesicles from the electric organ of Torpedo marmorata deduced from density measurements at different osmotic pressures. Eur J Biochem. 1978 Jul 3;87(3):453–458. doi: 10.1111/j.1432-1033.1978.tb12395.x. [DOI] [PubMed] [Google Scholar]
  7. Coronado R., Affolter H. Insulation of the conduction pathway of muscle transverse tubule calcium channels from the surface charge of bilayer phospholipid. J Gen Physiol. 1986 Jun;87(6):933–953. doi: 10.1085/jgp.87.6.933. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Cukierman S., Zinkand W. C., French R. J., Krueger B. K. Effects of membrane surface charge and calcium on the gating of rat brain sodium channels in planar bilayers. J Gen Physiol. 1988 Oct;92(4):431–447. doi: 10.1085/jgp.92.4.431. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Edry-Schiller J., Ginsburg S., Rahamimoff R. A bursting potassium channel in isolated cholinergic synaptosomes of Torpedo electric organ. J Physiol. 1991 Aug;439:627–647. doi: 10.1113/jphysiol.1991.sp018685. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Edry-Schiller J., Rahamimoff R. Activation and inactivation of the bursting potassium channel from fused Torpedo synaptosomes. J Physiol. 1993 Nov;471:659–678. doi: 10.1113/jphysiol.1993.sp019921. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Füldner H. H., Stadler H. 31P-NMR analysis of synaptic vesicles. Status of ATP and internal pH. Eur J Biochem. 1982 Jan;121(3):519–524. doi: 10.1111/j.1432-1033.1982.tb05817.x. [DOI] [PubMed] [Google Scholar]
  12. Hals G. D., Stein P. G., Palade P. T. Single channel characteristics of a high conductance anion channel in "sarcoballs". J Gen Physiol. 1989 Mar;93(3):385–410. doi: 10.1085/jgp.93.3.385. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Heuser J. E. Review of electron microscopic evidence favouring vesicle exocytosis as the structural basis for quantal release during synaptic transmission. Q J Exp Physiol. 1989 Dec;74(7):1051–1069. doi: 10.1113/expphysiol.1989.sp003333. [DOI] [PubMed] [Google Scholar]
  14. Hicks B. W., Parsons S. M. Characterization of the P-type and V-type ATPases of cholinergic synaptic vesicles and coupling of nucleotide hydrolysis to acetylcholine transport. J Neurochem. 1992 Apr;58(4):1211–1220. doi: 10.1111/j.1471-4159.1992.tb11331.x. [DOI] [PubMed] [Google Scholar]
  15. Johnson R. G., Jr Proton pumps and chemiosmotic coupling as a generalized mechanism for neurotransmitter and hormone transport. Ann N Y Acad Sci. 1987;493:162–177. doi: 10.1111/j.1749-6632.1987.tb27198.x. [DOI] [PubMed] [Google Scholar]
  16. Lee C. J., Dayanithi G., Nordmann J. J., Lemos J. R. Possible role during exocytosis of a Ca(2+)-activated channel in neurohypophysial granules. Neuron. 1992 Feb;8(2):335–342. doi: 10.1016/0896-6273(92)90299-s. [DOI] [PubMed] [Google Scholar]
  17. Luqmani Y. A. Nucleotide uptake by isolated cholinergic synaptic vesicles: evidence for a carrier of adenosine 5'-triphosphate. Neuroscience. 1981;6(6):1011–1021. doi: 10.1016/0306-4522(81)90067-1. [DOI] [PubMed] [Google Scholar]
  18. Maycox P. R., Hell J. W., Jahn R. Amino acid neurotransmission: spotlight on synaptic vesicles. Trends Neurosci. 1990 Mar;13(3):83–87. doi: 10.1016/0166-2236(90)90178-d. [DOI] [PubMed] [Google Scholar]
  19. Michaelson D. M., Angel I. Determination of delta pH in cholinergic synaptic vesicles: its effect on storage and release of acetylcholine. Life Sci. 1980 Jul 7;27(1):39–44. doi: 10.1016/0024-3205(80)90017-x. [DOI] [PubMed] [Google Scholar]
  20. Moczydlowski E., Alvarez O., Vergara C., Latorre R. Effect of phospholipid surface charge on the conductance and gating of a Ca2+-activated K+ channel in planar lipid bilayers. J Membr Biol. 1985;83(3):273–282. doi: 10.1007/BF01868701. [DOI] [PubMed] [Google Scholar]
  21. Morris S. J. The structure and stoichiometry of electric ray synaptic vesicles. Neuroscience. 1980;5(9):1509–1516. doi: 10.1016/0306-4522(80)90016-0. [DOI] [PubMed] [Google Scholar]
  22. Rahamimoff R., DeRiemer S. A., Sakmann B., Stadler H., Yakir N. Ion channels in synaptic vesicles from Torpedo electric organ. Proc Natl Acad Sci U S A. 1988 Jul;85(14):5310–5314. doi: 10.1073/pnas.85.14.5310. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Sato M., Inoue K., Kasai M. Ion channels on synaptic vesicle membranes studied by planar lipid bilayer method. Biophys J. 1992 Dec;63(6):1500–1505. doi: 10.1016/S0006-3495(92)81731-9. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Schmidt R., Zimmermann H., Whittaker V. P. Metal ion content of cholinergic synaptic vesicles isolated from the electric organ of Torpedo: effect of stimulation-induced transmitter release. Neuroscience. 1980;5(3):625–638. doi: 10.1016/0306-4522(80)90060-3. [DOI] [PubMed] [Google Scholar]
  25. Schuldiner S. A molecular glimpse of vesicular monoamine transporters. J Neurochem. 1994 Jun;62(6):2067–2078. doi: 10.1046/j.1471-4159.1994.62062067.x. [DOI] [PubMed] [Google Scholar]
  26. Stanley E. F., Ehrenstein G., Russell J. T. Evidence for anion channels in secretory vesicles. Neuroscience. 1988 Jun;25(3):1035–1039. doi: 10.1016/0306-4522(88)90056-5. [DOI] [PubMed] [Google Scholar]
  27. Tashiro T., Stadler H. Chemical composition of cholinergic synaptic vesicles from Torpedo marmorata based on improved purification. Eur J Biochem. 1978 Oct 16;90(3):479–487. doi: 10.1111/j.1432-1033.1978.tb12627.x. [DOI] [PubMed] [Google Scholar]
  28. Thomas-Reetz A. C., De Camilli P. A role for synaptic vesicles in non-neuronal cells: clues from pancreatic beta cells and from chromaffin cells. FASEB J. 1994 Feb;8(2):209–216. doi: 10.1096/fasebj.8.2.7907072. [DOI] [PubMed] [Google Scholar]
  29. Thomas L., Hartung K., Langosch D., Rehm H., Bamberg E., Franke W. W., Betz H. Identification of synaptophysin as a hexameric channel protein of the synaptic vesicle membrane. Science. 1988 Nov 18;242(4881):1050–1053. doi: 10.1126/science.2461586. [DOI] [PubMed] [Google Scholar]
  30. Walch-Solimena C., Jahn R., Südhof T. C. Synaptic vesicle proteins in exocytosis: what do we know? Curr Opin Neurobiol. 1993 Jun;3(3):329–336. doi: 10.1016/0959-4388(93)90125-i. [DOI] [PubMed] [Google Scholar]
  31. Whittaker V. P. Biophysical and biochemical studies of isolated cholinergic vesicles from Torpedo marmorata. Fed Proc. 1982 Sep;41(11):2759–2764. [PubMed] [Google Scholar]
  32. Zagotta W. N., Aldrich R. W. Voltage-dependent gating of Shaker A-type potassium channels in Drosophila muscle. J Gen Physiol. 1990 Jan;95(1):29–60. doi: 10.1085/jgp.95.1.29. [DOI] [PMC free article] [PubMed] [Google Scholar]

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