• Craig D Steinback, Petra Zubin, Toni Breskovic, Darija Bakovic, Nediljko Pivac, and Zeljko Dujic.
• Department of Physiology and Pharmacology, University of Calgary, Calgary, Canada. csteinba@ucalgary.ca
• J. Neurol. Sci. 2012 Oct 15;321(1-2):23-8.

AbstractEvidence suggests that the autonomic nervous system may actively regulate the cerebral vasculature. In this study, central hemodynamics and brain oxy-hemoglobin, deoxy-hemoglobin and total hemoglobin changes (bO₂Hb, bdHb and bTHb) were monitored during infusion of epinephrine (0.06 μg/kg/min over 6 min, and 0.12 μg/kg/min for 3 min) in 12 men. Epinephrine decreased mean arterial pressure (MAP) and total peripheral resistance (TPR), while heart rate (HR), stroke volume (SV) and cardiac output (CO) increased, but did not affect bO₂Hb, bdHb or bTHb. However, upon the cessation of epinephrine infusion an increase in both Oxy- and Total Hb occurred which peaked at 3 min post infusion (+6.0±4.6 and +4.9±4.8 μmol/L respectively, P<0.05) and persisted for 20 min post infusion (+1.5±2.2 and +1.8±2.7 μmol/L respectively, P<0.05). No evidence was found for reduction in cerebral oxygenation during a cold-pressor test. The results of the present study demonstrated that clinical doses of epinephrine result in a delayed increase in cortical blood volume due to an increase in Oxy-Hb, consistent with vasodilation.Copyright © 2012 Elsevier B.V. All rights reserved.

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