TY - JOUR
T1 - Effects of transmural pressure on brachial artery mean blood velocity dynamics in humans
AU - Lott, Mary E.J.
AU - Herr, Michael D.
AU - Sinoway, Lawrence I.
PY - 2002/12
Y1 - 2002/12
N2 - The effects of changes in transmural pressure on brachial artery mean blood velocity (MBV) were examined in humans. Transmural pressure was altered by using a specially designed pressure tank that raised or lowered forearm pressure by 50 mmHg within 0.2 s. Brachial MBV was measured with Doppler directly above the site of forearm pressure change. Pressure changes were evoked during resting conditions and after a 5-s handgrip contraction at 25% maximal voluntary contraction. The handgrip protocol selected was sufficiently vigorous to limit flow and sufficiently brief to prevent autonomic engagement. Changes in transmural pressure evoked directionally similar changes in MBV within 2 s. This was followed by large and rapid adjustments [-2.14 ± 0.24 cm/s (vasoconstriction) during negative pressure and +2.14 ± 0.45 cm/s (vasodilatation) during positive pressure]. These adjustments served to return MBV to resting levels. This regulatory influence remained operative after 5-s static handgrip contractions. Of note, changes in transmural pressure were capable of altering the timing of the peak MBV response (5 ± 0, 2 ± 0, 6 ± 1 s ambient, negative, and positive pressure, respectively) as well as the speed of MBV adjustment (-2.03 ± 0.18, -2.48 ± 0.15, -0.84 ± 0.19 cm.s-1.s-1 ambient, negative, and positive pressure, respectively) after handgrip contractions. Vascular responses, seen with changes in transmural pressure, provide evidence that the myogenic response is normally operative in the limb circulation of humans.
AB - The effects of changes in transmural pressure on brachial artery mean blood velocity (MBV) were examined in humans. Transmural pressure was altered by using a specially designed pressure tank that raised or lowered forearm pressure by 50 mmHg within 0.2 s. Brachial MBV was measured with Doppler directly above the site of forearm pressure change. Pressure changes were evoked during resting conditions and after a 5-s handgrip contraction at 25% maximal voluntary contraction. The handgrip protocol selected was sufficiently vigorous to limit flow and sufficiently brief to prevent autonomic engagement. Changes in transmural pressure evoked directionally similar changes in MBV within 2 s. This was followed by large and rapid adjustments [-2.14 ± 0.24 cm/s (vasoconstriction) during negative pressure and +2.14 ± 0.45 cm/s (vasodilatation) during positive pressure]. These adjustments served to return MBV to resting levels. This regulatory influence remained operative after 5-s static handgrip contractions. Of note, changes in transmural pressure were capable of altering the timing of the peak MBV response (5 ± 0, 2 ± 0, 6 ± 1 s ambient, negative, and positive pressure, respectively) as well as the speed of MBV adjustment (-2.03 ± 0.18, -2.48 ± 0.15, -0.84 ± 0.19 cm.s-1.s-1 ambient, negative, and positive pressure, respectively) after handgrip contractions. Vascular responses, seen with changes in transmural pressure, provide evidence that the myogenic response is normally operative in the limb circulation of humans.
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U2 - 10.1152/japplphysiol.00443.2002
DO - 10.1152/japplphysiol.00443.2002
M3 - Article
C2 - 12391123
AN - SCOPUS:0036892584
SN - 8750-7587
VL - 93
SP - 2137
EP - 2146
JO - Journal of applied physiology
JF - Journal of applied physiology
IS - 6
ER -