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

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 a(1c) 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 I (Ca,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.

Inhibitive Effects of FGF2/FGFR1 Pathway on Astrocyte-Mediated Inflammation in vivo and in vitro After Infrasound Exposure

“…Infrasound comes from two aspects, natural world and artificial activities, including volcanic eruptions, tsunami, aircraft flight, and weapons (Angelis et al, 2016). Infrasound can cause a systemic disease, known as vibroacoustic disease (VAD) (Ferreira et al, 2006; Mendes et al, 2006; Alves-Pereira and Castelo, 2007), which may cause damages to many systems, such as the central nervous system (CNS) (Yuan et al, 2009; Cheng et al, 2012; Zhang et al, 2016), digestion system (Da et al, 2006), cardiovascular system (Pei et al, 2009), respiratory system (Castelo et al, 2003; Branco et al, 2007), and other systems.…”

Exposure to infrasonic noise in agriculture

“…It must be borne in mind that similar studies in the human population have revealed many distressing adverse results of experimental research involving high exposures of infrasound, for example: -adverse influence on the respiratory and cardiovascular systems, metabolism of myocytes, endothelium of vessels, blood pressure and blood coagulation [26][27][28][29][30][31][32]; -adverse influence on the respiratory tissue [33]; -adverse influence on sexual behaviour [34]; -adversely affect the functions of neurons in different parts of the central and autonomic nervous systems, limbicreticular complex, hypothalamus, and other subcortical structures. These adverse influences can also cause diencephalic hypothalamic syndrome with sensor-somatic and autonomic visceral symptoms [35][36][37][38][39][40].…”

Infrasound Exposure Induces Apoptosis of Rat Cardiac Myocytes by Regulating the Expression of Apoptosis-Related Proteins

“…Recently, we reported infrasound-induced hemodynamics and ultrastructure damages in the rat myocardium [8]. Also, the L-type calcium currents in rat ventricular myocytes were dysregulated by infrasound [9]. These findings suggested important regulatory roles of infrasound on the cardiovascular systems.…”

“…Experimental studies have been reported that humans or various species of animals, such as rats and mice, exposed to infrasound at 90 dB and higher for short or long terms up to several months exhibited significant toxicological effects [8,21]. Why we currently used infrasound at 130 dB with the duration up to 72 h is based on the following reasons: (1) Previously, we found infrasound exposure at 130 dB significantly dysregulated the hemodynamics [8], ultrastructure [8], and L-type calcium currents [9] of cardiac myocytes and sexual behavior [5] in rats. As extension of previous studies, we used infrasound at 130 dB.…”