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. 1989 Jun;413:75–89. doi: 10.1113/jphysiol.1989.sp017642

Characterization of proton currents in neurones of the snail, Lymnaea stagnalis.

L Byerly 1, Y Suen 1
PMCID: PMC1189089  PMID: 2557442

Abstract

1. Internal perfusion voltage-clamp and inside-out patch-clamp techniques were used to study the voltage-dependent H+ currents in snail neurone cell bodies. 2. In whole cells the voltage-activated outward H+ current was measured 60 ms after stepping to +40 mV with an internal pH (pHi) of 5.9 and no internal K+([K+]i = 0), and the delayed K+ current was measured 60 ms after stepping to +40 mV with pHi = 7.3 and [K+]i = 74 mM. The mean H+ and K+ current densities were 14.6 +/- 7.8 and 38.2 +/- 14.0 nA/nF, respectively, giving a mean ratio of the H+ to K+ current of 0.4 +/- 0.2. There is not a strong correlation between the densities of the two kinds of outward currents found in different cells. 3. Inside-out patch studies reveal that the H+ and K+ currents are distributed quite differently in the membrane. While 85% of all patches had K+ current, only five out of thirty-eight patches studied had H+ currents. In those five patches the H+ currents measured at +30 mV ranged from 10.7 to 21.0 pA, and the ratio of the H+ and K+ currents at +30 mV was 0.83 +/- 0.38. The mean H+ and K+ currents for all thirty-eight patches were 1.9 +/- 4.9 and 10.5 +/- 7.9 pA, respectively. 4. The current distribution patterns demonstrate that the H+ current does not flow through the delayed K+ current channels even though the two currents have similar voltage dependence and time course. 5. The relative ability of various extracellular divalent cations to block the H+ current was found to be Cu2+ approximately equal to Zn2+ greater than Ni2+ greater than Cd2+ greater than Co2+ greater than Mn2+ greater than Mg2+ = Ca2+ = Ba2+. Since 100 microM-Zn2+ blocks the H+ current more than it blocks the Ca2+ current, it can be used to reduce the contamination of Ca2+ current measurements by the H+ current. 6. The magnitude of the H+ current has a stronger temperature sensitivity than does the magnitude of the delayed K+ current. The Q10 of the H+ current magnitude is 2.1 +/- 0.4, while the Q10 of the K+ current magnitude is 1.4 +/- 0.04. This suggests a higher activation energy may be involved in the conduction of the H+ current than for K+ current. 7. The smooth time course of the H+ current measured in patches indicates that the size of the unitary H+ current is very small.(ABSTRACT TRUNCATED AT 400 WORDS)

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Selected References

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

  1. Barish M. E., Baud C. A voltage-gated hydrogen ion current in the oocyte membrane of the axolotl, Ambystoma. J Physiol. 1984 Jul;352:243–263. doi: 10.1113/jphysiol.1984.sp015289. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Byerly L., Chase P. B., Stimers J. R. Calcium current activation kinetics in neurones of the snail Lymnaea stagnalis. J Physiol. 1984 Mar;348:187–207. doi: 10.1113/jphysiol.1984.sp015105. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Byerly L., Hagiwara S. Calcium currents in internally perfused nerve cell bodies of Limnea stagnalis. J Physiol. 1982 Jan;322:503–528. doi: 10.1113/jphysiol.1982.sp014052. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Byerly L., Meech R., Moody W., Jr Rapidly activating hydrogen ion currents in perfused neurones of the snail, Lymnaea stagnalis. J Physiol. 1984 Jun;351:199–216. doi: 10.1113/jphysiol.1984.sp015241. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Byerly L., Moody W. J. Intracellular calcium ions and calcium currents in perfused neurones of the snail, Lymnaea stagnalis. J Physiol. 1984 Jul;352:637–652. doi: 10.1113/jphysiol.1984.sp015314. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Byerly L., Moody W. J. Membrane currents of internally perfused neurones of the snail, Lymnaea stagnalis, at low intracellular pH. J Physiol. 1986 Jul;376:477–491. doi: 10.1113/jphysiol.1986.sp016165. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Fenwick E. M., Marty A., Neher E. Sodium and calcium channels in bovine chromaffin cells. J Physiol. 1982 Oct;331:599–635. doi: 10.1113/jphysiol.1982.sp014394. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Fukushima Y., Hagiwara S. Currents carried by monovalent cations through calcium channels in mouse neoplastic B lymphocytes. J Physiol. 1985 Jan;358:255–284. doi: 10.1113/jphysiol.1985.sp015550. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. 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]
  10. 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]
  11. Hamill O. P., Marty A., Neher E., Sakmann B., Sigworth F. J. Improved patch-clamp techniques for high-resolution current recording from cells and cell-free membrane patches. Pflugers Arch. 1981 Aug;391(2):85–100. doi: 10.1007/BF00656997. [DOI] [PubMed] [Google Scholar]
  12. Kostyuk P. G., Krishtal O. A., Shakhovalov Y. A. Separation of sodium and calcium currents in the somatic membrane of mollusc neurones. J Physiol. 1977 Sep;270(3):545–568. doi: 10.1113/jphysiol.1977.sp011968. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Lee K. S., Tsien R. W. Reversal of current through calcium channels in dialysed single heart cells. Nature. 1982 Jun 10;297(5866):498–501. doi: 10.1038/297498a0. [DOI] [PubMed] [Google Scholar]
  14. Meech R. W., Thomas R. C. Voltage-dependent intracellular pH in Helix aspersa neurones. J Physiol. 1987 Sep;390:433–452. doi: 10.1113/jphysiol.1987.sp016710. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Plant T. D., Standen N. B. Calcium current inactivation in identified neurones of Helix aspersa. J Physiol. 1981 Dec;321:273–285. doi: 10.1113/jphysiol.1981.sp013983. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Stevens C. F. Inferences about membrane properties from electrical noise measurements. Biophys J. 1972 Aug;12(8):1028–1047. doi: 10.1016/S0006-3495(72)86141-1. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Thomas R. C., Meech R. W. Hydrogen ion currents and intracellular pH in depolarized voltage-clamped snail neurones. Nature. 1982 Oct 28;299(5886):826–828. doi: 10.1038/299826a0. [DOI] [PubMed] [Google Scholar]

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