title: Cerebral oxygenation following epinephrine infusion.
abstract: Evidence 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.
authors.affiliation: Department of Physiology and Pharmacology, University of Calgary, Calgary, Canada. csteinba@ucalgary.ca
authors.forename: Craig D
authors.initials: CD
authors.lastname: Steinback
authors.forename: Petra
authors.initials: P
authors.lastname: Zubin
authors.forename: Toni
authors.initials: T
authors.lastname: Breskovic
authors.forename: Darija
authors.initials: D
authors.lastname: Bakovic
authors.forename: Nediljko
authors.initials: N
authors.lastname: Pivac
authors.forename: Zeljko
authors.initials: Z
authors.lastname: Dujic
mesh_terms: D000328:Adult; D001794:Blood Pressure / Q000187:drug effects; D002540:Cerebral Cortex / Q000187:drug effects* / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004562:Electrocardiography; D004837:Epinephrine / Q000494:pharmacology*; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D008297:Male; D010108:Oxyhemoglobins / Q000378:metabolism*; D019265:Spectroscopy, Near-Infrared; D018709:Statistics, Nonparametric; D013318:Stroke Volume / Q000187:drug effects; D014655:Vascular Resistance / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000494:pharmacology*; D055815:Young Adult
chemical_list: D006454:Hemoglobins; D010108:Oxyhemoglobins; D014662:Vasoconstrictor Agents; C100003:deoxyhemoglobin; D004837:Epinephrine