From supine to standing: in vivo segregation of myogenic and baroreceptor vasoconstriction in humans

Figures

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  Figure 1. Simplified diagram of the five maneuvers and its physiological interpretation.

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  Figure 2. Temporal records from the Portapres®. Panels from top to bottom correspond to interbeat interval, systolic blood pressure, and diastolic blood pressure of a typical young subject during the five maneuvers: (1) supine position with the hand at heart level, (2) supine position with one arm dependent, (3) upright with the arm dependent, (4) upright with the arm at the heart level, and (5) supine with the arm at the heart level.

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  Figure 3. Schematic detail of Figure 2 (systolic blood pressure (SBP) (upper panel), Fourier Transform of SBP (middle panel), and of interbeat interval (lower panel)). The entrance of the myogenic activity, baroreceptor activity, and the Mayer waves (typical of sympathetic effects) are shown with arrows. On spectral analysis, the myogenic activity with the arm dependent was not associated with an increase in the amplitude of low frequency (LF), whereas the baroreceptor activity induced by standing was associated with a large peak at LF frequencies.

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  Figure 4. Noninvasive temporal records from the photopletysmograph of the pulsatile arterial skin blood flow pulse pressure, AC recording (lower panel), and the nonpulsatile total blood volume of the finger, DC recording (upper panel) of a typical young subject during the five maneuvers.

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  Figure 5. Mean and standard deviation of the interbeat interval (upper panel), systolic blood pressure (middle panel), and total blood volume of the finger (lower panel) of all the subjects during the five maneuvers: (1) supine position with the hand at heart level, (2) supine position with one arm dependent, (3) upright with the arm dependent, (4) upright with the arm at the heart level, and (5) supine with the arm at the heart level.

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  Figure 6. Interbeat interval signal of a typical young subject. Each column corresponds to the different position illustrated on the top. Panels from top to bottom illustrate the time series, histogram, Poincaré plot, and PSD.

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  Figure 7. Systolic blood pressure signal of a typical young subject. Each column corresponds to the different position illustrated on the top. Panels from top to bottom illustrate the time series, histogram, Poincaré plot, and power spectral density.

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  Figure 8. Signal on the transition regions of a typical young subject. Each column corresponds to the different position changes illustrated on the top. On the top row are the IBI (black) and systolic blood pressure (SBP) (red) time series, Poincaré plots of the interbeat interval is on the middle row, and Poincaré's of the SBP on the bottom row.