Radial columns in autoradiographic images generated from tracer
methods for measuring cerebral cortical blood flow.
Bryan, Robert M., Jr, Ph. D. and Robert B. Duckrow, M. D.
Department of Anesthesiology, Baylor College of Medicine, Houston,
Texas 77030, Department of Neurology, University of Connecticut
School of Medicine, Farmington, CT 06030
APStracts 2:0068H, 1995.
Radial columns in the cerebral cortex, sometimes seen in
autoradiographic methods for measuring cerebral blood flow, were
studied. Radioactively labeled tracers were injected into the
internal carotid artery in pentobarbital anesthetized rats. The
cortical patterns of tracer uptake were determined using
autoradiography. When tracers for measuring cerebral blood flow were
administered, cortical columns were apparent in the autoradiograph.
The darker columns (higher tracer concentration) in the image aligned
with penetrating arterioles suggesting that the tracer was being
removed from the penetrating arterioles. In another experiment, 14C
-glucose was used as a qualitative blood flow tracer. Modeling of
glucose uptake predicts that 26-29% more glucose should be extracted
in the dark columns than the light columns if the columns represent
capillary blood flow. 14C-glucose did not produce the cortical
columns consistent with the model prediction. We conclude that
capillary blood flow in the cortex is not organized in radial columns
of higher and lower flow. The results support the idea that the flow
tracers are removed from blood primarily in the penetrating
arterioles.
Received 29 August 1994; accepted in final form 22 February 1995.
APS Manuscript Number H783-4.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 10 March 1995.