Acquirement of the autonomic nervous system modulation evaluated by heart rate variability in medaka (Oryzias latipes)

Figures

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  Fig 1. Average of steady-state heart rates, respiratory rates and examples of beat-by-beat heart rates. Group averaged steady-state heart rates were plotted under each condition (A). Group averaged respiratory rates (per min) were plotted under each condition in adult medaka (B). Standard deviations among five fish are plotted as error bars. Examples of beat-by-beat heart rate changes for 40 s under each experimental condition are presented (C-H). Control (C), 1 mM atropine (D), 100 μM propranolol (E), anesthesia with 80 μg/mL MS-222 (F), continuous light (G) and St. 36 embryo (H).

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  Fig 2. Power spectral analysis of HRV for 3 min in medaka. Power spectral density of HRV in adult control fish, administered with 1 mM atropine, 100 μM propranolol, 80 μg/mL MS-222 and under 1-week continuous light and St. 36 embryos were obtained by fast Fourier transformation using DADiSP software. The mean of power spectral density of HRV in five fish under each condition is shown. Low (0.015625–0.25 Hz), middle (0.25–0.65 Hz) and high (0.65–1.25 Hz) frequencies are shown as gray, black and white bars, respectively (A). The amount of power was added in each frequency range and error bars are standard deviations among five fish. Data from individual fish are indicated as black dots (B–D). B, 0.01625–0.25 Hz. C, 0.25–0.65 Hz. D, 0.65–1.25 Hz. *P ≤ 0.05, †P ≤ 0.01, ‡P ≤ 0.005, compared with control.

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  Fig 3. Automated extraction of heart movement in embryos. Sample pictures are at diastole and systole (A and B) in embryonic heart area view. Pixel intensities in the white circular ROI were extracted as numerical data. Twenty seconds of total intensity in white circles throughout the entire series were plotted after being smoothed by the 21-point moving average (C). a, atrium; v, ventricle. o, oil droplets. Scale bars indicated 100 μm.

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  Fig 4. Power spectral analysis of HRV for 3 min during development. Power spectral density and the mean of power spectral density of HRV in st.36 embryos (n = 5), 1 day post hatch (dph) larvae (n = 20), 7 dph larvae (n = 3) and 1 month old juvenile (n = 4) was calculated by fast Fourier transformation using DADiSP software. Low (0.015625–0.25 Hz), middle (0.25–0.65 Hz) and high (0.65–1.25 Hz) frequencies are shown in panels A, B and C, respectively. The amount of power was added in each frequency range and error bars are standard deviations among samples. A, 0.01625–0.25 Hz. B, 0.25–0.65 Hz. C, 0.65–1.25 Hz. ‡P ≤ 0.005; compared with st.36 embryos.