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. 1978 Jun 1;71(6):657–681. doi: 10.1085/jgp.71.6.657

Ionic blockage of the light-regulated sodium channels in isolated rod outer segments

PMCID: PMC2215111  PMID: 27574

Abstract

We have investigated, with osmotic techniques, the light-regulated Na+ channels in rod outer segments (ROS) and ROS fragments freshly isolated from the frog retina. Values of Na+ permeability (PNa) similar to those observed electrophysiologically in the retina were observed using the osmotic technique (continuous flow) described by Korenbrot and Cone. In the other osmotic techniques that we explored, PNa was greatly diminished, if not completely suppressed; however, we found with these techniques that antioxidant conditions (N2 atmosphere or EDTA) significantly increased PNa, suggesting that the Na+ channels are highly sensitivive to membrane oxidation. Using the continuous flow technique, we investigated the H+ and Ca++ dependence of the Na+ channels and found that both of these ions, at micromolar activities, can block the channels. Raising the external H+ activity decreases PNa (reversibly) in a single "sigmoidal" response with an apparent pKa of 5.8. Similarly, in the presence of the ionophores X537A or A23187 which allow equilibration of Ca++ across membranes, the Na+ channels are blocked when the external Ca++ activity is increased from 10(-7) to 10(- 5) M. This high sensitivity to both H+ and Ca++ ions suggests that high field strength anionic sites may exist in or near the Na+ channels and that the channels are blocked when these sites bind H+ or Ca++ ions.

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Selected References

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  1. Abrahamson E. W., Fager R. S., Mason W. T. Comparative properties of vertebrate and invertebrate photoreceptors. Exp Eye Res. 1974 Jan;18(1):51–67. doi: 10.1016/0014-4835(74)90043-8. [DOI] [PubMed] [Google Scholar]
  2. Baker P. F., Mason W. T. Proceedings: A method for the continuous measurement of net fluxes in isolated cells and subcellular particles: application to the study of calcium fluxes in disks isolated from frog retinal rod outer segments. J Physiol. 1974 Oct;242(2):50P–52P. [PubMed] [Google Scholar]
  3. Baylor D. A., Fuortes M. G. Electrical responses of single cones in the retina of the turtle. J Physiol. 1970 Mar;207(1):77–92. doi: 10.1113/jphysiol.1970.sp009049. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Begenisich T., Lynch C. Effects of internal divalent cations on voltage-clamped squid axons. J Gen Physiol. 1974 Jun;63(6):675–689. doi: 10.1085/jgp.63.6.675. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Bownds D., Brodie A. E. Light-sensitive swelling of isolated frog rod outer segments as an in vitro assay for visual transduction and dark adaptation. J Gen Physiol. 1975 Oct;66(4):407–425. doi: 10.1085/jgp.66.4.407. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Bownds D., Brodie A., Robinson W. E., Palmer R. D., Miller J., Shedlovsky A. Proceedings: Physiology and enzymology of frog photoreceptor membranes. Exp Eye Res. 1974 Mar;18(3):253–269. doi: 10.1016/0014-4835(74)90153-5. [DOI] [PubMed] [Google Scholar]
  7. Brodie A. E., Bownds D. Biochemical correlates of adaptation processes in isolated frog photoreceptor membranes. J Gen Physiol. 1976 Jul;68(1):1–11. doi: 10.1085/jgp.68.1.1. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Brown J. E., Pinto L. H. Ionic mechanism for the photoreceptor potential of the retina of Bufo marinus. J Physiol. 1974 Feb;236(3):575–591. doi: 10.1113/jphysiol.1974.sp010453. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Campbell D. T., Hille B. Kinetic and pharmacological properties of the sodium channel of frog skeletal muscle. J Gen Physiol. 1976 Mar;67(3):309–323. doi: 10.1085/jgp.67.3.309. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Cervetto L., Piccolino M. Synaptic transmission between photoreceptors and horizontal cells in the turtle retina. Science. 1974 Feb 1;183(4123):417–419. doi: 10.1126/science.183.4123.417. [DOI] [PubMed] [Google Scholar]
  11. Chabre M., Cavaggioni A. X-ray diffraction studies of retinal rods. II. Light effect on the osmotic properties. Biochim Biophys Acta. 1975 Mar 25;382(3):336–343. doi: 10.1016/0005-2736(75)90275-8. [DOI] [PubMed] [Google Scholar]
  12. Célis H., Estrada S., Montal M. Model translocators for divalent and monovalent ion transport in phospholipid membranes. I. The ion permeability induced in lipid bilayers by the antibiotic X-537A. J Membr Biol. 1974;18(2):187–199. doi: 10.1007/BF01870111. [DOI] [PubMed] [Google Scholar]
  13. Falk G., Fatt P. Rapid hydrogen ion uptake of rod outer segments and rhodopsin solutions on illumination. J Physiol. 1966 Mar;183(1):211–224. doi: 10.1113/jphysiol.1966.sp007861. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Farnsworth C. C., Dratz E. A. Oxidative damage of retinal rod outer segment membranes and the role of vitamin E. Biochim Biophys Acta. 1976 Sep 7;443(3):556–570. doi: 10.1016/0005-2736(76)90473-9. [DOI] [PubMed] [Google Scholar]
  15. Fletcher R. T., Chader G. J. Cyclic GMP: control of concentration by light in retinal photoreceptors. Biochem Biophys Res Commun. 1976 Jun 21;70(4):1297–1302. doi: 10.1016/0006-291x(76)91043-3. [DOI] [PubMed] [Google Scholar]
  16. Hagins W. A., Penn R. D., Yoshikami S. Dark current and photocurrent in retinal rods. Biophys J. 1970 May;10(5):380–412. doi: 10.1016/S0006-3495(70)86308-1. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Hagins W. A. The visual process: Excitatory mechanisms in the primary receptor cells. Annu Rev Biophys Bioeng. 1972;1:131–158. doi: 10.1146/annurev.bb.01.060172.001023. [DOI] [PubMed] [Google Scholar]
  18. Hagins W. A., Yoshikami S. Proceedings: A role for Ca2+ in excitation of retinal rods and cones. Exp Eye Res. 1974 Mar;18(3):299–305. doi: 10.1016/0014-4835(74)90157-2. [DOI] [PubMed] [Google Scholar]
  19. Hemminki K. Light-induced decrease in calcium binding to isolated bovine photoreceptors. Vision Res. 1975 Jan;15(1):69–72. doi: 10.1016/0042-6989(75)90061-9. [DOI] [PubMed] [Google Scholar]
  20. Hille B. Charges and potentials at the nerve surface. Divalent ions and pH. J Gen Physiol. 1968 Feb;51(2):221–236. doi: 10.1085/jgp.51.2.221. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Hille B. Ionic selectivity, saturation, and block in sodium channels. A four-barrier model. J Gen Physiol. 1975 Nov;66(5):535–560. doi: 10.1085/jgp.66.5.535. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Hyono A., Hendriks T., Daemen F. J., Bonting S. L. Movement of calcium through artificial lipid membranes and the effects of ionophores. Biochim Biophys Acta. 1975 Apr 21;389(1):34–46. doi: 10.1016/0005-2736(75)90383-1. [DOI] [PubMed] [Google Scholar]
  23. Korenbrot J. I., Brown D. T., Cone R. A. Membrane characteristics and osmotic behavior of isolated rod outer segments. J Cell Biol. 1973 Feb;56(2):389–398. doi: 10.1083/jcb.56.2.389. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Korenbrot J. I., Cone R. A. Dark ionic flux and the effects of light in isolated rod outer segments. J Gen Physiol. 1972 Jul;60(1):20–45. doi: 10.1085/jgp.60.1.20. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Liebman P. A. Light-dependent Ca++ content of rod outer segment disc membranes. Invest Ophthalmol. 1974 Sep;13(9):700–701. [PubMed] [Google Scholar]
  26. MCKNIGHT R. C., HUNTER F. E., Jr, OEHLERT W. H. MITOCHONDRIAL MEMBRANE GHOSTS PRODUCED BY LIPID PEROXIDATION INDUCED BY FERROUS ION. I. PRODUCTION AND GENERAL MORPHOLOGY. J Biol Chem. 1965 Aug;240:3439–3445. [PubMed] [Google Scholar]
  27. Mason W. T., Fager R. S., Abrahamson E. W. Ion fluxes in disk membranes of retinal rod outer segments. Nature. 1974 Feb 22;247(5442):562–563. doi: 10.1038/247562a0. [DOI] [PubMed] [Google Scholar]
  28. Murakami M., Shigematsu Y. Duality of conduction mechanism in bipolar cells of the frog retina. Vision Res. 1970 Jan;10(1):1–10. doi: 10.1016/0042-6989(70)90057-x. [DOI] [PubMed] [Google Scholar]
  29. Narahashi T., Anderson N. C., Moore J. W. Tetrodotoxin does not block excitation from inside the nerve membrane. Science. 1966 Aug 12;153(3737):765–767. doi: 10.1126/science.153.3737.765. [DOI] [PubMed] [Google Scholar]
  30. Novikov K. N., Kagan V. E., Shvedova A. A., Kozlov Iu P. Belok-lipidnye vzaimodeistviia pri perekisnom okislenii lipidov v fotoretseptornoi membrane. Biofizika. 1975 Nov-Dec;20(6):1039–1042. [PubMed] [Google Scholar]
  31. Oesterhelt D., Stoeckenius W. Functions of a new photoreceptor membrane. Proc Natl Acad Sci U S A. 1973 Oct;70(10):2853–2857. doi: 10.1073/pnas.70.10.2853. [DOI] [PMC free article] [PubMed] [Google Scholar]
  32. Ostroy S. E. Hydrogen ion changes of rhodopsin. pK changes and the thermal decay of metarhodopsin II380. Arch Biochem Biophys. 1974 Sep;164(1):275–284. doi: 10.1016/0003-9861(74)90032-0. [DOI] [PubMed] [Google Scholar]
  33. Pautler E. L., Su H. The effect of calcium on the Distal P III component of the frog ERG. Exp Eye Res. 1971 Jul;12(1):70–79. doi: 10.1016/0014-4835(71)90130-8. [DOI] [PubMed] [Google Scholar]
  34. Penn R. D., Hagins W. A. Kinetics of the photocurrent of retinal rods. Biophys J. 1972 Aug;12(8):1073–1094. doi: 10.1016/S0006-3495(72)86145-9. [DOI] [PMC free article] [PubMed] [Google Scholar]
  35. Penn R. D., Hagins W. A. Signal transmission along retinal rods and the origin of the electroretinographic a-wave. Nature. 1969 Jul 12;223(5202):201–204. doi: 10.1038/223201a0. [DOI] [PubMed] [Google Scholar]
  36. Pfeiffer D. R., Reed P. W., Lardy H. A. Ultraviolet and fluorescent spectral properties of the divalent cation ionophore A23187 and its metal ion complexes. Biochemistry. 1974 Sep 10;13(19):4007–4014. doi: 10.1021/bi00716a029. [DOI] [PubMed] [Google Scholar]
  37. RADDING C. M., WALD G. Acid-base properties of rhodopsin and opsin. J Gen Physiol. 1956 Jul 20;39(6):909–922. doi: 10.1085/jgp.39.6.909. [DOI] [PMC free article] [PubMed] [Google Scholar]
  38. Scarpa A., Baldassare J., Inesi G. The effect of calcium ionophores on fragmented sarcoplasmic reticulum. J Gen Physiol. 1972 Dec;60(6):735–749. doi: 10.1085/jgp.60.6.735. [DOI] [PMC free article] [PubMed] [Google Scholar]
  39. Scarpa A., de Gier J. Cation permeability of liposomes as a function of the chemical composition of the lipid bilayers. Biochim Biophys Acta. 1971 Sep 14;241(3):789–797. doi: 10.1016/0005-2736(71)90006-x. [DOI] [PubMed] [Google Scholar]
  40. Schacher S., Holtzman E., Hood D. C. Synaptic activity of frog retinal photoreceptors. A peroxidase uptake study. J Cell Biol. 1976 Jul;70(1):178–192. doi: 10.1083/jcb.70.1.178. [DOI] [PMC free article] [PubMed] [Google Scholar]
  41. Shevchenko T. F. Izmenenie aktivnosti ionov kal'tsiia pri osveshchenii suspenzii fragmentov naruzhnykh segmentov zritel'nykh kletok. Biofizika. 1976 Mar-Apr;21(2):321–323. [PubMed] [Google Scholar]
  42. Sillman A. J., Ito H., Tomita T. Studies on the mass receptor potential of the isolated frog retina. II. On the basis of the ionic mechanism. Vision Res. 1969 Dec;9(12):1443–1451. doi: 10.1016/0042-6989(69)90060-1. [DOI] [PubMed] [Google Scholar]
  43. Sillman A. J., Owen W. G., Fernandez H. R. The generation of the late receptor potential: an excitation-inhibition phenomenon. Vision Res. 1972 Sep;12(9):1519–1531. doi: 10.1016/0042-6989(72)90177-0. [DOI] [PubMed] [Google Scholar]
  44. Singer M. A., Bangham A. D. The consequences of inducing salt permeability in liposomes. Biochim Biophys Acta. 1971 Aug 13;241(2):687–692. doi: 10.1016/0005-2736(71)90068-x. [DOI] [PubMed] [Google Scholar]
  45. Singer M. A. Transfer of anions across phospholipid membranes. Can J Physiol Pharmacol. 1973 Jul;51(7):523–531. doi: 10.1139/y73-077. [DOI] [PubMed] [Google Scholar]
  46. Smith H. G., Jr, Fager R. S., Litman R. J. Light-activated calcium release from sonicated bovine retinal rod outer segment disks. Biochemistry. 1977 Apr 5;16(7):1399–1405. doi: 10.1021/bi00626a025. [DOI] [PubMed] [Google Scholar]
  47. Snyder W. Z. The effects of calcium and calcium-chelating agents on the aspartate-isolated frog PIII response. Exp Eye Res. 1974 Sep;19(3):201–214. doi: 10.1016/0014-4835(74)90138-9. [DOI] [PubMed] [Google Scholar]
  48. Sorbi R. T., Cavaggioni A. Effect of strong illumination on the ion efflux from the isolated discs of frog photoreceptors. Biochim Biophys Acta. 1975 Jul 18;394(4):577–585. doi: 10.1016/0005-2736(75)90143-1. [DOI] [PubMed] [Google Scholar]
  49. Szuts E. Z., Cone R. A. Calcium content of frog rod outer segments and discs. Biochim Biophys Acta. 1977 Jul 14;468(2):194–208. doi: 10.1016/0005-2736(77)90114-6. [DOI] [PubMed] [Google Scholar]
  50. Visser A. S., Postma P. W. Permeability of Azotobacter vinelandii to cations and anions. Biochim Biophys Acta. 1973 Mar 16;298(2):333–340. doi: 10.1016/0005-2736(73)90362-3. [DOI] [PubMed] [Google Scholar]
  51. Ward J. A., Ostroy S. E. Hydrogen ion effects and the vertebrate late receptor potential. Biochim Biophys Acta. 1972 Nov 17;283(2):373–380. doi: 10.1016/0005-2728(72)90253-8. [DOI] [PubMed] [Google Scholar]
  52. Weller M., Virmaux N., Mandel P. Role of light and rhodopsin phosphorylation in control of permeability of retinal rod outer segment disks to Ca2plus. Nature. 1975 Jul 3;256(5512):68–70. doi: 10.1038/256068a0. [DOI] [PubMed] [Google Scholar]
  53. Werblin F. S. Regenerative hyperpolarization in rods. J Physiol. 1975 Jan;244(1):53–81. doi: 10.1113/jphysiol.1975.sp010784. [DOI] [PMC free article] [PubMed] [Google Scholar]
  54. Winkler B. S. Calcium and the fast and slow components of P3 of the electroretinogram of the isolated rat retina. Vision Res. 1974 Jan;14(1):9–15. doi: 10.1016/0042-6989(74)90110-2. [DOI] [PubMed] [Google Scholar]
  55. Woodhull A. M. Ionic blockage of sodium channels in nerve. J Gen Physiol. 1973 Jun;61(6):687–708. doi: 10.1085/jgp.61.6.687. [DOI] [PMC free article] [PubMed] [Google Scholar]
  56. Yoshikami S., Robinson W. E., Hagins W. A. Topology of the outer segment membranes of retinal rods and cones revealed by a fluorescent probe. Science. 1974 Sep 27;185(4157):1176–1179. doi: 10.1126/science.185.4157.1176. [DOI] [PubMed] [Google Scholar]
  57. Zuckerman R. Ionic analysis of photoreceptor membrane currents. J Physiol. 1973 Dec;235(2):333–354. doi: 10.1113/jphysiol.1973.sp010390. [DOI] [PMC free article] [PubMed] [Google Scholar]
  58. Zuckerman R. Mechanisms of photoreceptor current generation in light and darkness. Nat New Biol. 1971 Nov 3;234(44):29–31. doi: 10.1038/newbio234029a0. [DOI] [PubMed] [Google Scholar]

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