Advertisement

Pflügers Archiv - European Journal of Physiology

, Volume 465, Issue 12, pp 1727–1740 | Cite as

Methylmercury decreases cellular excitability by a direct blockade of sodium and calcium channels in bovine chromaffin cells: an integrative study

  • J. Fuentes-Antrás
  • E. Osorio-Martínez
  • M. Ramírez-Torres
  • I. Colmena
  • J. C. Fernández-Morales
  • J. M. Hernández-GuijoEmail author
Ion channels, receptors and transporters

Abstract

Methylmercury, a potent environmental pollutant responsible for fatal food poisoning, blocked calcium channels of bovine chromaffin cells in a time- and concentration-dependent manner with an IC50 of 0.93 μM. This blockade was not reversed upon wash-out and was greater at more depolarising holding potentials (i.e. 21 % at −110 mV and 60 % at −50 mV, after 3 min perfusion with methylmercury). In ω-toxins-sensitive calcium channels, methylmercury caused a higher blockade of I Ba than in ω-toxins-resistant ones, in which a lower blockade was detected. The sodium current was also blocked by acute application of methylmercury in a time- and concentration-dependent manner with an IC50 of 1.05 μM. The blockade was not reversed upon wash-out of the drug. The drug inhibited sodium current at all test potentials and shows a shift of the I-V curve to the left of about 10 mV. Intracellular dialysis with methylmercury caused no blockade of calcium or sodium channels. Voltage-dependent potassium current was not affected by methylmercury. Calcium- and voltage-dependent potassium current was also drastically depressed. This blockade was related to the prevention of Ca2+ influx through voltage-dependent calcium channels coupled to BK channels. Under current-clamp conditions, the blockade of ionic current present during the generation and termination of action potentials led to a drastic alteration of cellular excitability. The application of methylmercury greatly reduced the shape and the number of electrically evoked action potentials. Taken together, these results point out that the neurotoxic action evoked by methylmercury may be associated to alteration of cellular excitability by blocking ionic currents responsible for the generation and termination of action potentials.

Keywords

Chromaffin cells Methylmercury Calcium channels Action potentials Sodium channels 

Notes

Acknowledgements

The authors thank Dr. Luis Gandía for helpful discussion and further acknowledge the support provided by “Fundación Teófilo Hernando” to the present study.

References

  1. 1.
    Akiyama T, Yamazaki T, Kawada T, Shimizu S, Sugimachi M, Shirai M (2010) Role of Ca2+-activated K+ channels in catecholamine release from in vivo rat adrenal medulla. Neurochem Int 56(2):263–269PubMedCrossRefGoogle Scholar
  2. 2.
    Albillos A, García AG, Olivera BM, Gandia L (1996) Re-evaluation of P/Q Ca2+ channel components of Ba2+ currents in bovine chromaffin cells superfused with solutions containing low and high Ba2+ concentrations. Pflügers Arch Eur J Physiol 432:1030–1038CrossRefGoogle Scholar
  3. 3.
    Aosaki T, Kasai H (1989) Characterization of two kinds of high-voltage-activated Ca2+-channel currents in chick sensory neurons Differential sensitivity to dihydrophyridines and omegaconotoxin GVIA. Pflügers Arch Eur J Physiol 414:150–156CrossRefGoogle Scholar
  4. 4.
    Aschner M, Aschner JL (1990) Mercury neurotoxicity: mechanisms of blood–brain barrier transport. Neurosci Biobehav Rev 14:169–176PubMedCrossRefGoogle Scholar
  5. 5.
    Atchison WD (2005) Is chemical neurotransmission altered specifically during methylmercury induced cerebellar dysfunction? Trends Pharmacol Sci 26:549–557PubMedCrossRefGoogle Scholar
  6. 6.
    Atchison W, Hare M (1994) Mechanisms of methylmercury induces neurotoxicity. FASEB J 8(9):622–629PubMedGoogle Scholar
  7. 7.
    Atchison WD, Narahashi T (1982) Methylmercury-induced depression of neuromuscular transmission in the rat. Neurotoxicology 3:37–50PubMedGoogle Scholar
  8. 8.
    Augustine GJ, Neher E (1992) Neuronal signalling takes the local route. Curr Opin Neurobiol 2:302–307PubMedCrossRefGoogle Scholar
  9. 9.
    Bakir F, Damluji SF, Amin-Zaki L, Murtadha M, Khalidi A, Al-Rawi N, Tikriti S, Dahahir HI, Clarkson TW, Smith JC, Doherty RA (1973) Methylmercury poisoning in Iraq. Science 181:239–240CrossRefGoogle Scholar
  10. 10.
    Baldelli P, Forni PE, Carbone E (2000) BDNF, NT-3 and NGF induce distinct new Ca2+ channel synthesis in developing hippocampal neurons. Eur J Neurosci 12(11):4017–4032PubMedCrossRefGoogle Scholar
  11. 11.
    Burgoyne RD, Alvarez de Toledo G (2000) Fusion proteins and fusion pores Workshop: regulated exocytosis and the vesicle cycle. EMBO Rep 1(4):304–307PubMedCrossRefGoogle Scholar
  12. 12.
    Eyl TB (1971) Organic-mercury food poisoning. New Eng J Med 284(13):706–709PubMedCrossRefGoogle Scholar
  13. 13.
    Franco JL, Posser T, Dunkley PR, Dickson PW, Mattos JJ, Marting R, Bainy AC, Marques MR, Dafre AL, Farina M (2009) Methylmercury neurotoxicity is associated with inhibition of the antioxidant enzyme glutathione peroxidase. Free Radic Biol Med 47:449–457PubMedCrossRefGoogle Scholar
  14. 14.
    Friberg L, Mottet NK (1989) Accumulation of methylmercury and inorganic mercury in the brain. Biol Trace Elem Res 21:201–206PubMedCrossRefGoogle Scholar
  15. 15.
    García AG, García de Diego AM, Gandía L, Borges R, García-Sancho J (2006) Calcium signaling and exocytosis in adrenal chromaffin cells. Physiol Rev 86(4):1093–1131PubMedCrossRefGoogle Scholar
  16. 16.
    García-Palomero E, Cuchillo-Ibánez I, García AG, Renart J, Albillos A, Montiel C (2000) Greater diversity than previously thought of chromaffin cell Ca2+ channels, derived from mRNA identification studies. FEBS Lett 481:235–239PubMedCrossRefGoogle Scholar
  17. 17.
    Hajela RK, Shuang-Quing P, Atchison WD (2003) Comparative effects of methylmercury and Hg2+ on human neuronal N- and R-type high-voltage activated calcium channels transiently expressed in human embryonic kidney 293 cells. J Pharmacol Exp Ther 3(306):1129–1136CrossRefGoogle Scholar
  18. 18.
    Hamill OP, Marty A, Neher E, Sakmann B, Sigworth FJ (1981) Improved patch-clamp techniques for high-resolution current recording from cells and cell-free membrane patches. Pflügers Arch Eur J Physiol 391:85–100CrossRefGoogle Scholar
  19. 19.
    Hernández A, Segura-Chama P, Jiménez N, García AG, Hernández-Cruz A, Hernández-Guijo JM (2011) Modulation by endogenously released ATP and opioids of chromaffin cell calcium channels in mouse adrenal slices. Am J Physiol Cell Physiol 300:C610–C623PubMedCrossRefGoogle Scholar
  20. 20.
    Hernandez-Guijo JM, Gandía L, de Pascual R, Garcia AG (1997) Differential effects of the neuroprotectant lubeluzole on bovine and mouse chromaffin cell calcium channel subtypes. Br J Pharmacol 122:275–285PubMedCrossRefGoogle Scholar
  21. 21.
    Hodking A, Huxley A (1952) A quantitative description of membrane current and its application to conduction and excitation in nerve. J Physiol 117:500–544Google Scholar
  22. 22.
    Katz B, Miledi R (1968) The role of calcium in neuromuscular facilitation. J Physiol 195(2):481–492PubMedGoogle Scholar
  23. 23.
    Korn SJ, Horn R (1989) Influence of sodium-calcium exchange on calcium current rundown and the duration of calcium-dependent chloride currents in pituitary cells, studied with whole cell and perforated patch recording. J Gen Physiol 94:789–812PubMedCrossRefGoogle Scholar
  24. 24.
    Leonhardt R, Haas H, Büsselberg D (1996) Methylmercury reduces voltage-activated currents of rat dorsal root ganglion neurons. Naunyn Schmiedeberg’s Arch Pharmacol 354(4):532–538CrossRefGoogle Scholar
  25. 25.
    Livett BG (1984) Adrenal medullary chromaffin cells in vitro. Physiol Rev 64:1103–1161PubMedGoogle Scholar
  26. 26.
    Mancini JD, Autio DM, Atchison WD (2009) Continuous exposure to low concentrations of methylmercury impairs cerebellar granule cell migration in organotypic slice culture. Neurotoxicology 30(2):203–208PubMedCrossRefGoogle Scholar
  27. 27.
    Marcantoni A, Baldelli P, Hernandez-Guijo JM, Comunanza V, Carabelli V, Carbone E (2007) L-type calcium channels in adrenal chromaffin cells: role in pace-making and secretion. Cell Calcium 42(4–5):397–408PubMedCrossRefGoogle Scholar
  28. 28.
    Marcantoni A, Vandael DH, Mahapatra S, Carabelli V, Sinnegger-Brauns MJ, Striessnig J, Carbone E (2010) Loss of Cav1.3 channels reveals the critical role of L-type and BK channel coupling in pacemaking mouse adrenal chromaffin cells. J Neurosci 30(2):491–504PubMedCrossRefGoogle Scholar
  29. 29.
    Marrion NV, Tavalin SJ (1998) Selective activation of Ca2+-activated K+ channels by co-localized Ca2+ channels in hippocampal neurons. Nature 395:900–905PubMedCrossRefGoogle Scholar
  30. 30.
    Marty A, Neher E (1985) Potassium channels in cultured bovine adrenal chromaffin cells. J Physiol 367:117–141PubMedGoogle Scholar
  31. 31.
    Mintz IM (1994) Block of Ca channels in rat central neurons by the spider toxin omega-Aga-IIIA. J Neurosci 14:2844–2853PubMedGoogle Scholar
  32. 32.
    Moro MA, López MG, Gandía L, Michelena P, García AG (1990) Separation and culture of living adrenaline- and noradrenaline-containing cells from bovine adrenal medullae. Anal Biochem 185:243–248PubMedCrossRefGoogle Scholar
  33. 33.
    Myers GJ, Davidson PW (1998) Prenatal methylmercury exposure and children: neurologic, developmental, and behavioral research. Environ Health Perspect 106(Suppl 3):841–847PubMedCrossRefGoogle Scholar
  34. 34.
    Naraghi M, Neher E (1997) Linearized buffered Ca2+ diffusion in microdomains and its implications for calculation of [Ca2+] at the mouth of a calcium channel. J Neurosci 17:6961–6973PubMedGoogle Scholar
  35. 35.
    Neher E (1986) Concentration profiles of intracellular calcium in the presence of a diffusible chelator. Exp Brain Res Ser 14:80–96Google Scholar
  36. 36.
    Ochi T (2002) Methylmercury, but not inorganic mercury, causes abnormality of centrosome integrity (multiple foci of gamma-tubulin), multipolar spindles and multinucleated cells without microtubule disruption in cultured Chinese hamster V79 cells. Toxicology 175:111–121PubMedCrossRefGoogle Scholar
  37. 37.
    Peng S, Hajela RK, Atchison WD (2002) Effects of methylmercury on human neuronal L-type calcium channels transiently expressed in human embryonic kidney cells (HEK-293). J Pharmacol Exp Ther 302:424–432PubMedCrossRefGoogle Scholar
  38. 38.
    Plummer MR, Logothetis DE, Hess P (1989) Elementary properties and pharmacological sensitivities of calcium channels in mammalian peripheral neurons. Neuron 2:1453–1463PubMedCrossRefGoogle Scholar
  39. 39.
    Prakriya M, Lingle CJ (1999) Activation of BK channels during brief depolarizations or action potential waveforms requires Ca2+ influx through L-and Q-type Ca2+ channels in rat chromaffin cells. J Neurophysiol 81:2267–2278PubMedGoogle Scholar
  40. 40.
    Prakriya M, Lingle CJ (2000) Activation of BK channels in rat chromaffin cells requires summation of Ca2+ influx from multiple Ca2+ channels. J Neurophysiol 84:1123–1135PubMedGoogle Scholar
  41. 41.
    Protti DA, Uchitel OD (1993) Transmitter release and presynaptic Ca2+ currents blocked by the spider toxin ω-Aga-IVA. Neuroreport 5:333–336PubMedCrossRefGoogle Scholar
  42. 42.
    Quandt FN, Kato E, Narahashi T (1982) Effects of methylmercury on electrical responses of neuroblastoma cells. Neurotoxicology 3(4):205–220PubMedGoogle Scholar
  43. 43.
    Rae J, Cooper K, Gates P, Watsky M (1991) Low access resistance perforated patch recordings using amphotericin B. J Neurosci Methods 37:15–26PubMedCrossRefGoogle Scholar
  44. 44.
    Randall A, Tsien RW (1995) Pharmacological dissection of multiple types of Ca2+ channel currents in rat cerebellar neurons. J Neurosci 15:2995–3012PubMedGoogle Scholar
  45. 45.
    Rao MV, Purohit AR (2011) Neuroprotection by melatonin on mercury induced toxicity in the rat brain. J Pharm Pharmacol 2:375–385CrossRefGoogle Scholar
  46. 46.
    Roberts WM (1993) Spatial calcium buffering in saccular hair cells. Nature 363:74–76PubMedCrossRefGoogle Scholar
  47. 47.
    Sarafian T, Verity MA (1991) Oxidative mechanisms underlying methyl mercury neurotoxicity. Int J Dev Neurosci 9:147–153PubMedCrossRefGoogle Scholar
  48. 48.
    Scott RS, Bustillo D, Olivos-Oré LA, Cuchillo-Ibañez I, Barahona MV, Carbone E, Artalejo AR (2011) Contribution of BK channels to action potential repolarisation at minimal cytosolic Ca2+ concentration in chromaffin cells. Pflügers Arch Eur J Physiol 462:545–557CrossRefGoogle Scholar
  49. 49.
    Shafer TJ, Atchison WD (1992) Effects of methylmercury on perineural Na+ and Ca2+-dependent potentials at neuromuscular junctions of the mouse. Brain Res 595(2):215–219PubMedCrossRefGoogle Scholar
  50. 50.
    Shafer TJ, Meacham CA, Barone S Jr (2002) Effects of prolonged exposure to nanomolar concentrations of methylmercury on voltaje-sensitive sodium and calcium currents in PC12 cells. Dev Brain Res 136(2):151–164CrossRefGoogle Scholar
  51. 51.
    Sheng M, Wyszynzki M (1997) Ion channel targeting in neurons. Bioessays 19:847–853PubMedCrossRefGoogle Scholar
  52. 52.
    Shieh CC, Coghlan M, Sullivan JP, Gopalakrishnan M (2000) Potassium channels: molecular defects, diseases, and therapeutic opportunities. Pharmacol Rev 52(4):557–554PubMedGoogle Scholar
  53. 53.
    Sirois JE, Atchison WD (2000) Methylmercury Affects Multiple Subtypes of Calcium Channels in Rat Cerebellar Granule Cells. Toxicol Appl Pharmacol 167:1–11PubMedCrossRefGoogle Scholar
  54. 54.
    Solano CR, Prakriya M, Ding JP, Lingle CJ (1995) Inactivating and non-inactivating Ca2+ and voltage-dependent K+ current in rat adrenal chromaffin cells. J Neurosci 15:6110–6123Google Scholar
  55. 55.
    Stocker M (2004) Ca2+-activated K+ channels: molecular determinants and function of the SK family. Nat rev 5:768–770Google Scholar
  56. 56.
    Sun L, Xiong Y, Zeng X, Wu Y, Pan N, Lingle CJ, Qu A, Ding J (2009) Differential regulation of action potentials by inactivating and noninactivating BK channels in rat adrenal chromaffin cells. Biophys J 7:1832–1842CrossRefGoogle Scholar
  57. 57.
    Szücs A, Angiello C, Salànki J, Carpenter DO (1997) Effects of inorganic mercury and methylmercury on the ionic currents of cultured rat hippocampal neurons. Cell Mol Neurobiol 17(3):273–288PubMedCrossRefGoogle Scholar
  58. 58.
    Takahashi T, Momiyamaa A (1993) Different types of calcium channels mediate central synaptic transmission. Natur 366:156–158CrossRefGoogle Scholar
  59. 59.
    Takeuchi T (1982) Pathology of Minamata disease With special reference to its pathogenesis. Acta Pathol Jpn 32(1):73–99PubMedGoogle Scholar
  60. 60.
    Tarabová B, Kerejová M, Sulová Z, Drabová M, Lacinová L (2006) Inorganic mercury and methylmercury inhibit the Cav3.1 channel expressed in human embryonic kidney cells by different mechanisms. J Pharmacol Exp Ther 317:418–427PubMedCrossRefGoogle Scholar
  61. 61.
    Wheeler DB, Randall A, Tsien RW (1994) Roles of N-type and Q-type Ca2+ channels in supporting hippocampal synaptic transmission. Science 264:107–111PubMedCrossRefGoogle Scholar
  62. 62.
    Wisgirda ME, Dryer SE (1994) Functional dependence of Ca2+ activated K+ current on L- and N-type Ca2+ channels: differences between chicken sympathetic and parasympathetic neurons suggest different regulatory mechanisms. Proc Natl Acad Sci USA 91(7):2858–2862PubMedCrossRefGoogle Scholar
  63. 63.
    Yuan Y, Atchison WD (1993) Disruption by methylmercury of membrane excitability and synaptic transmission of CA1 neurons in hippocampal slices of the rat. Toxicol Appl Pharmacol 120(2):203–215PubMedCrossRefGoogle Scholar
  64. 64.
    Yuan Y, Atchison WD (1995) Methylmercury acts at multiple sites to block hippocampal synaptic transmission. J Pharmacol Exp Ther 275(3):1308–1316PubMedGoogle Scholar
  65. 65.
    Yuan Y, Atchison WD (2007) Methylmercury-induced increase of intracellular Ca2+ increases spontanous synaptic current frequency in rat cerebellar slices. Mol Pharmacol 71:1109–1121PubMedCrossRefGoogle Scholar
  66. 66.
    Yuan Y, Otero-Montañez JKL, Yao A, Herden CJ, Sirois JE, Atchinson WD (2005) Inwardly rectifying and voltage-gated outward potassium channels exhibit low sensitivity to methylmercury. Neurotoxicol 26:439–454CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • J. Fuentes-Antrás
    • 1
    • 2
  • E. Osorio-Martínez
    • 1
    • 2
  • M. Ramírez-Torres
    • 1
    • 2
  • I. Colmena
    • 1
    • 2
  • J. C. Fernández-Morales
    • 1
    • 2
  • J. M. Hernández-Guijo
    • 1
    • 2
    • 3
    Email author
  1. 1.Department of Pharmacology and Therapeutic, School of MedicineUniversidad Autónoma de MadridMadridSpain
  2. 2.Institute “Teófilo Hernando”, School of MedicineUniversidad Autónoma de MadridMadridSpain
  3. 3.Institute “Investigación Sanitaria Hospital de la Princesa”, School of MedicineUniversidad Autónoma de MadridMadridSpain

Personalised recommendations