Coupling between the blood lactate-to-pyruvate ratio and MCA Vmean at the onset of exercise in humans
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Coupling between the blood lactate-to-pyruvate ratio and MCA Vmean at the onset of exercise in humans. / Rasmussen, Peter; Madsen, Camilla A; Nielsen, Henning B; Zaar, Morten; Gjedde, Albert; Secher, Niels H; Quistorff, Bjørn.
In: Journal of Applied Physiology, Vol. 107, No. 6, 2009, p. 1799-805.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Coupling between the blood lactate-to-pyruvate ratio and MCA Vmean at the onset of exercise in humans
AU - Rasmussen, Peter
AU - Madsen, Camilla A
AU - Nielsen, Henning B
AU - Zaar, Morten
AU - Gjedde, Albert
AU - Secher, Niels H
AU - Quistorff, Bjørn
N1 - Keywords: Adolescent; Adult; Blood Flow Velocity; Blood Pressure; Catheters, Indwelling; Cerebrovascular Circulation; Exercise; Heart Rate; Humans; Lactic Acid; Male; Middle Cerebral Artery; Models, Biological; Oxygen Consumption; Pyruvic Acid; Signal Processing, Computer-Assisted; Time Factors; Ultrasonography, Doppler, Transcranial
PY - 2009
Y1 - 2009
N2 - Activation-induced increase in cerebral blood flow is coupled to enhanced metabolic activity, maybe with brain tissue redox state and oxygen tension as key modulators. To evaluate this hypothesis at the onset of exercise in humans, blood was sampled at 0.1 to 0.2 Hz from the radial artery and right internal jugular vein, while middle cerebral artery mean flow velocity (MCA V(mean)) was recorded. Both the arterial and venous lactate-to-pyruvate ratio increased after 10 s (P < 0.05), and the arterial ratio remained slightly higher than the venous (P < 0.05). The calculated average cerebral capillary oxygen tension decreased by 2.7 mmHg after 5 s (P < 0.05), while MCA V(mean) increased only after 30 s. Furthermore, there was an unaccounted cerebral carbohydrate uptake relative to the uptake of oxygen that became significant 50 s after the onset of exercise. These findings support brain tissue redox state and oxygenation as potential modulators of an increase in cerebral blood flow at the onset of exercise.
AB - Activation-induced increase in cerebral blood flow is coupled to enhanced metabolic activity, maybe with brain tissue redox state and oxygen tension as key modulators. To evaluate this hypothesis at the onset of exercise in humans, blood was sampled at 0.1 to 0.2 Hz from the radial artery and right internal jugular vein, while middle cerebral artery mean flow velocity (MCA V(mean)) was recorded. Both the arterial and venous lactate-to-pyruvate ratio increased after 10 s (P < 0.05), and the arterial ratio remained slightly higher than the venous (P < 0.05). The calculated average cerebral capillary oxygen tension decreased by 2.7 mmHg after 5 s (P < 0.05), while MCA V(mean) increased only after 30 s. Furthermore, there was an unaccounted cerebral carbohydrate uptake relative to the uptake of oxygen that became significant 50 s after the onset of exercise. These findings support brain tissue redox state and oxygenation as potential modulators of an increase in cerebral blood flow at the onset of exercise.
U2 - 10.1152/japplphysiol.00468.2009
DO - 10.1152/japplphysiol.00468.2009
M3 - Journal article
C2 - 19779155
VL - 107
SP - 1799
EP - 1805
JO - Journal of Applied Physiology
JF - Journal of Applied Physiology
SN - 8750-7587
IS - 6
ER -
ID: 18787093