Temporal dynamics of the partial pressure of brain tissue oxygen during functional forepaw stimulation in rats.
The partial pressure of tissue oxygen (pO2) was measured in rat somatosensory cortex during periodic electrical forepaw stimulation of either 1 min or 4 s in duration, and correlated with simultaneous laser Doppler flowmetry. For both stimulus durations, a transient decrease in tissue pO2 preceded blood flow changes, followed by a peak in blood flow and an overshoot in tissue pO2. With protracted stimulation, tissue pO2 remained only slightly above pre-stimulus baseline, while blood flow was maintained at a reduced plateau phase. A sustained post-stimulus undershoot in tissue pO2 was observed only for the 1 min stimulus. These findings suggest a complex dynamic relationship between oxygen utilization and blood flow.
Ances
B M
BM
Department of Neurology, University of Pennsylvania School of Medicine, 3400 Spruce Street, Philadelphia, PA 19104, USA.
Buerk
D G
DG
Greenberg
J H
JH
Detre
J A
JA
D000344:Afferent Pathways / Q000502:physiology*; D000818:Animals; D002560:Cerebrovascular Circulation / Q000502:physiology*; D004558:Electric Stimulation; D005552:Forelimb / Q000294:innervation / Q000502:physiology; D017078:Laser-Doppler Flowmetry; D008297:Male; D008465:Mechanoreceptors / Q000502:physiology; D008839:Microelectrodes; D009474:Neurons / Q000378:metabolism; D017711:Nonlinear Dynamics; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology*; D010313:Partial Pressure; D010812:Physical Stimulation; D051381:Rats; D017207:Rats, Sprague-Dawley; D013003:Somatosensory Cortex / Q000166:cytology / Q000378:metabolism*; D013997:Time Factors
D010100:Oxygen