Cardiovascular Toxicology

, Volume 9, Issue 2, pp 70–77

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 

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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