The effects of ketamine–xylazine anesthesia on cerebral blood flow and oxygenation observed using nuclear magnetic resonance perfusion imaging and electron paramagnetic resonance oximetry

Ketamine–xylazine is a commonly used anesthetic for laboratory rats. Previous results showed that rats anesthetized with ketamine–xylazine can have a much lower cerebral partial pressure of oxygen ( P tO 2), compared to unanesthetized and isoflurane anesthetized rats. The underlying mechanisms for t...

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Bibliographic Details
Published in:Brain research 2001-09, Vol.913 (2), p.174-179
Main Authors: Lei, Hao, Grinberg, O., Nwaigwe, C.I., Hou, H.G., Williams, H., Swartz, H.M., Dunn, J.F.
Format: Article
Language:English
Subjects:
Adrenergic alpha-Agonists - pharmacology
Anesthetics, Dissociative - pharmacology
Anesthetics, Inhalation - pharmacology
Anesthetics. Neuromuscular blocking agents
Animals
Biological and medical sciences
Cerebral Arteries - drug effects
Cerebral Arteries - metabolism
Cerebral blood flow
Cerebrovascular Circulation - drug effects
Cerebrovascular Circulation - physiology
Drug Interactions - physiology
Electron paramagnetic resonance
Energy Metabolism - drug effects
Energy Metabolism - physiology
Isoflurane - pharmacology
Ketamine
Ketamine - pharmacology
Magnetic Resonance Imaging - methods
Magnetic resonance perfusion imaging
Male
Medical sciences
Neuropharmacology
oximetry
Oximetry - methods
Oxygen - metabolism
Oxygen Consumption - drug effects
Oxygen Consumption - physiology
Oxygenation
Pharmacology. Drug treatments
Prosencephalon - drug effects
Prosencephalon - metabolism
Rats
Rats, Sprague-Dawley
Xylazine
Xylazine - pharmacology
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Summary:Ketamine–xylazine is a commonly used anesthetic for laboratory rats. Previous results showed that rats anesthetized with ketamine–xylazine can have a much lower cerebral partial pressure of oxygen ( P tO 2), compared to unanesthetized and isoflurane anesthetized rats. The underlying mechanisms for the P tO 2 reduction need to be elucidated. In this study, we measured regional cerebral blood flow (CBF) using nuclear magnetic resonance (NMR) perfusion imaging and cortical P tO 2 using electron paramagnetic resonance (EPR) oximetry in the forebrain of rats under isoflurane, ketamine, ketamine–xylazine and isoflurane–xylazine anesthesia. The results show that in ventilated rats ketamine at a dose of 50 mg/kg does not induce significant changes in CBF, compared to isoflurane. Ketamine–xylazine in combination causes 25–65% reductions in forebrain CBF in a region-dependent manner. Adding xylazine to isoflurane anesthesia results in similar regional reductions in CBF. EPR oximetry measurements show ketamine increases cortical P tO 2 while xylazine decreases cortical P tO 2. The xylazine induced reduction in CBF could explain the reduced brain oxygenation observed in ketamine–xylazine anesthetized rats.
ISSN:0006-8993
1872-6240
DOI:10.1016/S0006-8993(01)02786-X