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. 2000 Apr;78(4):1835–1851. doi: 10.1016/S0006-3495(00)76733-6

Effects of cytoplasmic and luminal pH on Ca(2+) release channels from rabbit skeletal muscle.

D R Laver 1, K R Eager 1, L Taoube 1, G D Lamb 1
PMCID: PMC1300778  PMID: 10733964

Abstract

Ryanodine receptor (RyR)-Ca(2+) release channels from rabbit skeletal muscle were incorporated into lipid bilayers. The effects of cytoplasmic and luminal pH were studied separately over the pH range 5-8, using half-unit intervals. RyR activity (at constant luminal pH of 7.5) was inhibited at acidic cytoplasmic pH, with a half-inhibitory pH (pH(I)) approximately 6.5, irrespective of bilayer potential and of whether the RyRs were activated by cytoplasmic Ca(2+) (50 microM), ATP (2 or 5 mM), or both. Inhibition occurred within approximately 1 s and could be fully reversed within approximately 1 s after brief inhibition or within approximately 30-60 s after longer exposure to acidic cytosolic pH. There was no evidence of any hysteresis in the cytoplasmic pH effect. Ryanodine-modified channels were less sensitive to pH inhibition, with pH(I) at approximately 5.5, but the inhibition was similarly reversible. Steady-state open and closed dwell times of RyRs during cytoplasmic pH inhibition suggest a mechanism where the binding of one proton inhibits the channel and the binding of two to three additional protons promotes further inhibited states. RyR activity was unaffected by luminal pH in the pH range 7.5 to 6.0. At lower luminal pH (5-5.5) most RyRs were completely inhibited, and raising the pH again produced partial to full recovery in only approximately 50% of cases, with the extent of recovery not detectably different between pH 7.5 and pH 9. The results indicate that isolated skeletal muscle RyRs are not inhibited as strongly by low cytoplasmic and luminal pH, as suggested by previous single-channel studies.

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Selected References

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  1. Ahern G. P., Junankar P. R., Dulhunty A. F. Single channel activity of the ryanodine receptor calcium release channel is modulated by FK-506. FEBS Lett. 1994 Oct 3;352(3):369–374. doi: 10.1016/0014-5793(94)01001-3. [DOI] [PubMed] [Google Scholar]
  2. Allen D. G., Lännergren J., Westerblad H. Muscle cell function during prolonged activity: cellular mechanisms of fatigue. Exp Physiol. 1995 Jul;80(4):497–527. doi: 10.1113/expphysiol.1995.sp003864. [DOI] [PubMed] [Google Scholar]
  3. Baker A. J., Brandes R., Weiner M. W. Effects of intracellular acidosis on Ca2+ activation, contraction, and relaxation of frog skeletal muscle. Am J Physiol. 1995 Jan;268(1 Pt 1):C55–C63. doi: 10.1152/ajpcell.1995.268.1.C55. [DOI] [PubMed] [Google Scholar]
  4. Brooks S. P., Storey K. B. Bound and determined: a computer program for making buffers of defined ion concentrations. Anal Biochem. 1992 Feb 14;201(1):119–126. doi: 10.1016/0003-2697(92)90183-8. [DOI] [PubMed] [Google Scholar]
  5. Bruton J. D., Lännergren J., Westerblad H. Effects of CO2-induced acidification on the fatigue resistance of single mouse muscle fibers at 28 degrees C. J Appl Physiol (1985) 1998 Aug;85(2):478–483. doi: 10.1152/jappl.1998.85.2.478. [DOI] [PubMed] [Google Scholar]
  6. Chu A., Dixon M. C., Saito A., Seiler S., Fleischer S. Isolation of sarcoplasmic reticulum fractions referable to longitudinal tubules and junctional terminal cisternae from rabbit skeletal muscle. Methods Enzymol. 1988;157:36–46. doi: 10.1016/0076-6879(88)57066-0. [DOI] [PubMed] [Google Scholar]
  7. Chung S. H., Moore J. B., Xia L. G., Premkumar L. S., Gage P. W. Characterization of single channel currents using digital signal processing techniques based on Hidden Markov Models. Philos Trans R Soc Lond B Biol Sci. 1990 Sep 29;329(1254):265–285. doi: 10.1098/rstb.1990.0170. [DOI] [PubMed] [Google Scholar]
  8. Copello J. A., Barg S., Onoue H., Fleischer S. Heterogeneity of Ca2+ gating of skeletal muscle and cardiac ryanodine receptors. Biophys J. 1997 Jul;73(1):141–156. doi: 10.1016/S0006-3495(97)78055-X. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Donoso P., Beltrán M., Hidalgo C. Luminal pH regulated calcium release kinetics in sarcoplasmic reticulum vesicles. Biochemistry. 1996 Oct 15;35(41):13419–13425. doi: 10.1021/bi9616209. [DOI] [PubMed] [Google Scholar]
  10. Fitts R. H. Cellular mechanisms of muscle fatigue. Physiol Rev. 1994 Jan;74(1):49–94. doi: 10.1152/physrev.1994.74.1.49. [DOI] [PubMed] [Google Scholar]
  11. Hain J., Nath S., Mayrleitner M., Fleischer S., Schindler H. Phosphorylation modulates the function of the calcium release channel of sarcoplasmic reticulum from skeletal muscle. Biophys J. 1994 Nov;67(5):1823–1833. doi: 10.1016/S0006-3495(94)80664-2. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Harrison S. M., Bers D. M. The effect of temperature and ionic strength on the apparent Ca-affinity of EGTA and the analogous Ca-chelators BAPTA and dibromo-BAPTA. Biochim Biophys Acta. 1987 Aug 13;925(2):133–143. doi: 10.1016/0304-4165(87)90102-4. [DOI] [PubMed] [Google Scholar]
  13. Herrmann-Frank A., Varsányi M. Enhancement of Ca2+ release channel activity by phosphorylation of the skeletal muscle ryanodine receptor. FEBS Lett. 1993 Oct 18;332(3):237–242. doi: 10.1016/0014-5793(93)80640-g. [DOI] [PubMed] [Google Scholar]
  14. Hidalgo C., Donoso P. Luminal calcium regulation of calcium release from sarcoplasmic reticulum. Biosci Rep. 1995 Oct;15(5):387–397. doi: 10.1007/BF01788370. [DOI] [PubMed] [Google Scholar]
  15. Kamp F., Donoso P., Hidalgo C. Changes in luminal pH caused by calcium release in sarcoplasmic reticulum vesicles. Biophys J. 1998 Jan;74(1):290–296. doi: 10.1016/S0006-3495(98)77786-0. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Kawasaki T., Kasai M. Regulation of calcium channel in sarcoplasmic reticulum by calsequestrin. Biochem Biophys Res Commun. 1994 Mar 30;199(3):1120–1127. doi: 10.1006/bbrc.1994.1347. [DOI] [PubMed] [Google Scholar]
  17. Kourie J. I., Laver D. R., Ahern G. P., Dulhunty A. F. A calcium-activated chloride channel in sarcoplasmic reticulum vesicles from rabbit skeletal muscle. Am J Physiol. 1996 Jun;270(6 Pt 1):C1675–C1686. doi: 10.1152/ajpcell.1996.270.6.C1675. [DOI] [PubMed] [Google Scholar]
  18. Lamb G. D., Recupero E., Stephenson D. G. Effect of myoplasmic pH on excitation-contraction coupling in skeletal muscle fibres of the toad. J Physiol. 1992 Mar;448:211–224. doi: 10.1113/jphysiol.1992.sp019037. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Lamb G. D., Stephenson D. G. Effect of Mg2+ on the control of Ca2+ release in skeletal muscle fibres of the toad. J Physiol. 1991 Mar;434:507–528. doi: 10.1113/jphysiol.1991.sp018483. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Lamb G. D., Stephenson D. G. Effects of intracellular pH and [Mg2+] on excitation-contraction coupling in skeletal muscle fibres of the rat. J Physiol. 1994 Jul 15;478(Pt 2):331–339. doi: 10.1113/jphysiol.1994.sp020253. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Laver D. R., Baynes T. M., Dulhunty A. F. Magnesium inhibition of ryanodine-receptor calcium channels: evidence for two independent mechanisms. J Membr Biol. 1997 Apr 1;156(3):213–229. doi: 10.1007/s002329900202. [DOI] [PubMed] [Google Scholar]
  22. Laver D. R., Curtis B. A. Surface potentials measure ion concentrations near lipid bilayers during rapid solution changes. Biophys J. 1996 Aug;71(2):722–731. doi: 10.1016/S0006-3495(96)79271-8. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Laver D. R., Lamb G. D. Inactivation of Ca2+ release channels (ryanodine receptors RyR1 and RyR2) with rapid steps in [Ca2+] and voltage. Biophys J. 1998 May;74(5):2352–2364. doi: 10.1016/S0006-3495(98)77944-5. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Laver D. R., Owen V. J., Junankar P. R., Taske N. L., Dulhunty A. F., Lamb G. D. Reduced inhibitory effect of Mg2+ on ryanodine receptor-Ca2+ release channels in malignant hyperthermia. Biophys J. 1997 Oct;73(4):1913–1924. doi: 10.1016/S0006-3495(97)78222-5. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Laver D. R., Roden L. D., Ahern G. P., Eager K. R., Junankar P. R., Dulhunty A. F. Cytoplasmic Ca2+ inhibits the ryanodine receptor from cardiac muscle. J Membr Biol. 1995 Sep;147(1):7–22. doi: 10.1007/BF00235394. [DOI] [PubMed] [Google Scholar]
  26. Ma J. Desensitization of the skeletal muscle ryanodine receptor: evidence for heterogeneity of calcium release channels. Biophys J. 1995 Mar;68(3):893–899. doi: 10.1016/S0006-3495(95)80265-1. [DOI] [PMC free article] [PubMed] [Google Scholar]
  27. Ma J., Fill M., Knudson C. M., Campbell K. P., Coronado R. Ryanodine receptor of skeletal muscle is a gap junction-type channel. Science. 1988 Oct 7;242(4875):99–102. doi: 10.1126/science.2459777. [DOI] [PubMed] [Google Scholar]
  28. Ma J., Zhao J. Highly cooperative and hysteretic response of the skeletal muscle ryanodine receptor to changes in proton concentrations. Biophys J. 1994 Aug;67(2):626–633. doi: 10.1016/S0006-3495(94)80522-3. [DOI] [PMC free article] [PubMed] [Google Scholar]
  29. Marengo J. J., Hidalgo C., Bull R. Sulfhydryl oxidation modifies the calcium dependence of ryanodine-sensitive calcium channels of excitable cells. Biophys J. 1998 Mar;74(3):1263–1277. doi: 10.1016/S0006-3495(98)77840-3. [DOI] [PMC free article] [PubMed] [Google Scholar]
  30. Marks P. W., Maxfield F. R. Preparation of solutions with free calcium concentration in the nanomolar range using 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid. Anal Biochem. 1991 Feb 15;193(1):61–71. doi: 10.1016/0003-2697(91)90044-t. [DOI] [PubMed] [Google Scholar]
  31. Meissner G. Adenine nucleotide stimulation of Ca2+-induced Ca2+ release in sarcoplasmic reticulum. J Biol Chem. 1984 Feb 25;259(4):2365–2374. [PubMed] [Google Scholar]
  32. Meissner G., Darling E., Eveleth J. Kinetics of rapid Ca2+ release by sarcoplasmic reticulum. Effects of Ca2+, Mg2+, and adenine nucleotides. Biochemistry. 1986 Jan 14;25(1):236–244. doi: 10.1021/bi00349a033. [DOI] [PubMed] [Google Scholar]
  33. Meissner G. Ryanodine receptor/Ca2+ release channels and their regulation by endogenous effectors. Annu Rev Physiol. 1994;56:485–508. doi: 10.1146/annurev.ph.56.030194.002413. [DOI] [PubMed] [Google Scholar]
  34. Melzer W., Herrmann-Frank A., Lüttgau H. C. The role of Ca2+ ions in excitation-contraction coupling of skeletal muscle fibres. Biochim Biophys Acta. 1995 May 8;1241(1):59–116. doi: 10.1016/0304-4157(94)00014-5. [DOI] [PubMed] [Google Scholar]
  35. Michalak M., Dupraz P., Shoshan-Barmatz V. Ryanodine binding to sarcoplasmic reticulum membrane; comparison between cardiac and skeletal muscle. Biochim Biophys Acta. 1988 Apr 22;939(3):587–594. doi: 10.1016/0005-2736(88)90106-x. [DOI] [PubMed] [Google Scholar]
  36. Miller C., Racker E. Ca++-induced fusion of fragmented sarcoplasmic reticulum with artificial planar bilayers. J Membr Biol. 1976;30(3):283–300. doi: 10.1007/BF01869673. [DOI] [PubMed] [Google Scholar]
  37. Rousseau E., Pinkos J. pH modulates conducting and gating behaviour of single calcium release channels. Pflugers Arch. 1990 Feb;415(5):645–647. doi: 10.1007/BF02583520. [DOI] [PubMed] [Google Scholar]
  38. Rousseau E., Smith J. S., Meissner G. Ryanodine modifies conductance and gating behavior of single Ca2+ release channel. Am J Physiol. 1987 Sep;253(3 Pt 1):C364–C368. doi: 10.1152/ajpcell.1987.253.3.C364. [DOI] [PubMed] [Google Scholar]
  39. Shomer N. H., Mickelson J. R., Louis C. F. Caffeine stimulation of malignant hyperthermia-susceptible sarcoplasmic reticulum Ca2+ release channel. Am J Physiol. 1994 Nov;267(5 Pt 1):C1253–C1261. doi: 10.1152/ajpcell.1994.267.5.C1253. [DOI] [PubMed] [Google Scholar]
  40. Shomer N. H., Mickelson J. R., Louis C. F. Ion selectivity of porcine skeletal muscle Ca2+ release channels is unaffected by the Arg615 to Cys615 mutation. Biophys J. 1994 Aug;67(2):641–646. doi: 10.1016/S0006-3495(94)80524-7. [DOI] [PMC free article] [PubMed] [Google Scholar]
  41. Sigworth F. J., Sine S. M. Data transformations for improved display and fitting of single-channel dwell time histograms. Biophys J. 1987 Dec;52(6):1047–1054. doi: 10.1016/S0006-3495(87)83298-8. [DOI] [PMC free article] [PubMed] [Google Scholar]
  42. Sitsapesan R., Williams A. J. Regulation of current flow through ryanodine receptors by luminal Ca2+. J Membr Biol. 1997 Oct 1;159(3):179–185. doi: 10.1007/s002329900281. [DOI] [PubMed] [Google Scholar]
  43. Timerman A. P., Ogunbumni E., Freund E., Wiederrecht G., Marks A. R., Fleischer S. The calcium release channel of sarcoplasmic reticulum is modulated by FK-506-binding protein. Dissociation and reconstitution of FKBP-12 to the calcium release channel of skeletal muscle sarcoplasmic reticulum. J Biol Chem. 1993 Nov 5;268(31):22992–22999. [PubMed] [Google Scholar]
  44. Tinker A., Lindsay A. R., Williams A. J. A model for ionic conduction in the ryanodine receptor channel of sheep cardiac muscle sarcoplasmic reticulum. J Gen Physiol. 1992 Sep;100(3):495–517. doi: 10.1085/jgp.100.3.495. [DOI] [PMC free article] [PubMed] [Google Scholar]
  45. Tripathy A., Meissner G. Sarcoplasmic reticulum lumenal Ca2+ has access to cytosolic activation and inactivation sites of skeletal muscle Ca2+ release channel. Biophys J. 1996 Jun;70(6):2600–2615. doi: 10.1016/S0006-3495(96)79831-4. [DOI] [PMC free article] [PubMed] [Google Scholar]
  46. Tripathy A., Xu L., Mann G., Meissner G. Calmodulin activation and inhibition of skeletal muscle Ca2+ release channel (ryanodine receptor). Biophys J. 1995 Jul;69(1):106–119. doi: 10.1016/S0006-3495(95)79880-0. [DOI] [PMC free article] [PubMed] [Google Scholar]
  47. Witcher D. R., Kovacs R. J., Schulman H., Cefali D. C., Jones L. R. Unique phosphorylation site on the cardiac ryanodine receptor regulates calcium channel activity. J Biol Chem. 1991 Jun 15;266(17):11144–11152. [PubMed] [Google Scholar]
  48. Xu L., Mann G., Meissner G. Regulation of cardiac Ca2+ release channel (ryanodine receptor) by Ca2+, H+, Mg2+, and adenine nucleotides under normal and simulated ischemic conditions. Circ Res. 1996 Dec;79(6):1100–1109. doi: 10.1161/01.res.79.6.1100. [DOI] [PubMed] [Google Scholar]

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