Cardiovascular Toxicology

, Volume 9, Issue 2, pp 70–77 | Cite as

Influence of Infrasound Exposure on the Whole L-type Calcium Currents in Rat Ventricular Myocytes

  • Zhaohui Pei
  • Zhiqiang Zhuang
  • Pingxi Xiao
  • Jingzao Chen
  • Hanfei Sang
  • Jun Ren
  • Zhenbiao Wu
  • Guangmei Yan
Article

Abstract

This study was designed to examine the effect of infrasound exposure (5 Hz at 130 dB) on whole-cell L-type Ca2+ currents (WLCC) in rat ventricular myocytes and the underlying mechanism(s) involved. Thirty-two adult Sprague-Dawley rats were randomly assigned to infrasound exposure and control groups. [Ca2+]i, WLCC, mRNA expression of the a1c subunit of L-type Ca2+ channels (LCC), and SERCA2 protein were examined on day 1, 7, and 14 after initiation of infrasound exposure. Fluo-3/AM fluorescence and the laser scanning confocal microscope techniques were used to measure [Ca2+]i in freshly isolated ventricular myocytes. The Ca2+ fluorescence intensity (FI), denoting [Ca2+]i in cardiomyocytes, was significantly elevated in a time-dependent manner in the exposure groups. There was a significant increase in WLCC in the 1-day group and a further significant increase in the 7- and 14-day groups. LCC mRNA expression measured by RT-PCR revealed a significant rise in the 1-day group and a significant additional rise in the 7- and 14-day groups compared with control group. SERCA2 expression was significantly upregulated in the 1-day group followed by an overt decrease in the 7- and 14-day groups. Prolonged exposure of infrasound altered WLCC in rat cardiomyocytes by shifting the steady-state inactivation curves to the right (more depolarized direction) without altering the slope and biophysical properties of ICa,L. Taken together, our data suggest that changes in [Ca2+]I levels as well as expression of LCC and SERCA2 may contribute to the infrasound exposure-elicited cardiac response.

Keywords

Infrasound Whole L-type Ca2+ currents L-type Ca2+ channel Sarco(endo)plasmic reticulum Ca2+-ATPase Fluorescence intensity 

References

  1. 1.
    Pei, Z., Sang, H., Li, R., Xiao, P., He, J., Zhuang, Z., et al. (2007). Infrasound-induced hemodynamics, ultrastructure, and molecular changes in the rat myocardium. Environmental Toxicology, 22, 169–175. doi:10.1002/tox.20244.PubMedCrossRefGoogle Scholar
  2. 2.
    Nekhoroshe, A. S., & Glinchikov, V. V. (1991). Morphofunctional changes in the myocardium under exposure to infrasound. NVB Noise and Vibration Bulletin, 12, 15–17.Google Scholar
  3. 3.
    Chen, J. Z., Pei, Z. H., Zhu, M. Z., Zhuang, Z. Q., Pei, J. M., & Liu, J. (2005). Effects of infrasound of 8 Hz at 90 dB on the ultra-structure of myocardium. Chinese Heart Journal, 17, 216–217.Google Scholar
  4. 4.
    Yamasumi, Y., Shiraishi, T., Miyashita, K., Kuroda, M., Luo, W., & Taniuchi, T. S. (1994). The pituitary adrenocortical response in rats exposed to fluctuating infrasound. Journal of Low Frequency Noise and Vibration, 13, 89–93.Google Scholar
  5. 5.
    Slarve, R. N., & Johnson, D. L. (1975). Human whole body exposure to infrasound. Aviation, Space and Environmental Medicine, 46, 428–431.Google Scholar
  6. 6.
    Liu, Z. H., Chen, J. Z., Tang, Y., Chen, D., Ding, G. R., Liu, J., et al. (2004). Effects of infrasound on changes of intracellular calcium ion concentration and on expression of RyRs in hippocampus of rat brain. Journal of Low Frequency Noise and Vibration, 23, 159–165. doi:10.1260/0263092042863618.CrossRefGoogle Scholar
  7. 7.
    Bers, D. M., & Perez-Reyes, E. (1999). Ca2+ channels in cardiac myocytes: Structure and function in Ca influx and intracellular Ca2+ release. Cardiovascular Research, 42, 339–360. doi:10.1016/S0008-6363(99)00038-3.PubMedCrossRefGoogle Scholar
  8. 8.
    Maclennan, D. H. (1970). Purification and properties of an adenosine triphosphatase from sarcoplasmic reticulum. The Journal of Biological Chemistry, 245, 4508–4518.PubMedGoogle Scholar
  9. 9.
    Walsh, K. B., & Long, K. J. (1992). Inhibition of heart calcium and chloride currents by sodium iodide. Specific attenuation in cAMP-dependent protein kinase-mediated regulation. The Journal of General Physiology, 100, 847–865. doi:10.1085/jgp.100.5.847.PubMedCrossRefGoogle Scholar
  10. 10.
    Walsh, K. B., & Parks, G. E. (2002). Changes in cardiac myocyte morphology alter the properties of voltage-gated ion channels. Cardiovascular Research, 55, 64–75. doi:10.1016/S0008-6363(02)00403-0.PubMedCrossRefGoogle Scholar
  11. 11.
    Hamill, O. P., Marty, A., Neher, E., Sakmann, B., & Sigworth, J. (1981). Improved patch-clamp techniques for high resolution current recordings from cells and cell-free membrane patches. Pflügers Archiv, 391, 85–100. doi:10.1007/BF00656997.PubMedCrossRefGoogle Scholar
  12. 12.
    Wijetunge, S., Lymn, J. S., & Hughes, A. D. (2000). Effects of protein tyrosine kinase inhibitors on voltage-operated calcium channel currents in vascular smooth muscle cells and pp60 (c-src) kinase activity. British Journal of Pharmacology, 129, 1347–1354. doi:10.1038/sj.bjp.0703186.PubMedCrossRefGoogle Scholar
  13. 13.
    Inui, M., Wang, S., Saito, A., & Fleischer, S. (1998). Characterization of junctional and longitudinal sarcoplasmic reticulum from heart muscle. The Journal of Biological Chemistry, 263, 10843–10850.Google Scholar
  14. 14.
    Sánchez, G., Hidalgo, C., & Donoso, P. (2003). Kinetic studies of calcium-induced calcium release in cardiac sarcoplasmic reticulum vesicles. Biophysical Journal, 84, 2319–2330. doi:10.1016/S0006-3495(03)75037-1.PubMedCrossRefGoogle Scholar
  15. 15.
    Zhuang, Z. Q., Pei, Z. H., & Chen, J. Z. (2007). Infrasound-induced changes on sexual behavior in male rats and some underlying mechanism. Environmental Toxicology and Pharmacology, 23, 111–114. doi:10.1016/j.etap.2006.07.009.CrossRefGoogle Scholar
  16. 16.
    Fei, Z., Zhang, X., Li, Z. G., Liu, E. Y., Bai, H. M., Chen, J. Z., et al. (2001). The changes and significance of TXA2 and PGI2 metabolism after rat infrasonic brain damage. Journal of Low Frequency Noise and Vibration, 20, 33–37. doi:10.1260/0263092011492966.CrossRefGoogle Scholar
  17. 17.
    Fei, Z., Zhang, X., Wang, X. F., Li, Z. G., Lu, L., Liu, X. Z., et al. (2000). The changes of rat blood-brain barrier permeability and expression of heat shock protein 70 after infrasonic damage. Journal of Low Frequency Noise and Vibration, 19, 93–99. doi:10.1260/0263092001492840.CrossRefGoogle Scholar
  18. 18.
    Hudman, D., Rainbow, R. D., Lawrence, C. L., & Standen, N. B. (2002). The origin of calcium overload in rat cardiac myocytes following metabolic inhibition with 2,4-dinitrophenol. Journal of Molecular and Cellular Cardiology, 34, 859–871. doi:10.1006/jmcc.2002.2024.PubMedCrossRefGoogle Scholar
  19. 19.
    Xia, M., Salat, J. J., Figueroa, D. J., Lawlor, A. M., Liang, H. A., Liu, Y., et al. (2004). Functional expression of L- and T-type Ca2+ channels in murine HL-1 cells. Journal of Molecular and Cellular Cardiology, 36, 111–119. doi:10.1016/j.yjmcc.2003.10.007.PubMedCrossRefGoogle Scholar
  20. 20.
    Andrzej, M., Janczewski, H. A., & Spurgeon, E. G. (2002). Action potential prolongation in cardiac myocytes of old rats is an adaptation to sustain youthful intracellular Ca2+ regulation. Journal of Molecular and Cellular Cardiology, 34, 641–648. doi:10.1006/jmcc.2002.2004.CrossRefGoogle Scholar
  21. 21.
    Thomas, N., Rana, M. T., Ken-ichi, K., & Naranjan, S. D. (2002). Ca2+-overload inhibits the cardiac SR Ca2+–calmodulin protein kinase activity. Biochemical and Biophysical Research Communications, 293, 727–732. doi:10.1016/S0006-291X(02)00287-5.CrossRefGoogle Scholar
  22. 22.
    Xu, A. T., Netticadan, D. L., & Jones, N. N. (1999). Serine phosphorylation of the sarcoplasmic reticulum Ca2+-ATPase in the intact beating rabbit heart. Biochemical and Biophysical Research Communications, 264, 241–246. doi:10.1006/bbrc.1999.1491.PubMedCrossRefGoogle Scholar
  23. 23.
    Konrad, F. F., Birgit, B., Erland, E., & Robert, H. G. (2003). Sarcoplasmic reticulum Ca-ATPase modulates cardiac contraction and relaxation. Cardiovascular Research, 57, 20–27. doi:10.1016/S0008-6363(02)00694-6.CrossRefGoogle Scholar

Copyright information

© Humana Press 2009

Authors and Affiliations

  • Zhaohui Pei
    • 1
  • Zhiqiang Zhuang
    • 2
  • Pingxi Xiao
    • 3
  • Jingzao Chen
    • 4
  • Hanfei Sang
    • 4
  • Jun Ren
    • 5
  • Zhenbiao Wu
    • 6
  • Guangmei Yan
    • 1
  1. 1.Department of Pharmacology, Zhongshan Medical CollegeSun Yat-Sen UniversityGuangzhouChina
  2. 2.Department of Rehabilitation MedicineThe Second Affiliated Hospital of Sun Yat-Sen UniversityGuangzhouChina
  3. 3.Department of CardiologyThe First Affiliated Hospital of Nanjing UniversityNanjingChina
  4. 4.Infrasound Lab of Xijing HospitalThe Fourth Military Medical UniversityXi’anChina
  5. 5.Center for Cardiovascular Research and Alternative MedicineUniversity of Wyoming College of Health SciencesLaramieUSA
  6. 6.Department of Clinical Immunology, Xijing HospitalThe Fourth Military Medical UniversityXi’anChina

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