Stroke, Vol 12, 581-588, Copyright © 1981 by American Heart Association
Simultaneous measurement of blood flow and glucose metabolism by autoradiographic techniques
G Mies, I Niebuhr and KA Hossmann
A double tracer autoradiographic technique using 131I-iodo-antipyrine and
14C-deoxyglucose is presented for the simultaneous measurement of blood
flow and cerebral glucose utilization in the same animal. 131I is a gamma
emitting isotope with a half life of 8.06 days and can be detected with
adequate resolution on standard autoradiographic films. Autoradiograms are
made before and after decay of 131I; the time interval between the 2
exposures and the concentration of the 2 tracers is adjusted to avoid
significant cross-contamination. In this way, 2 film exposures are obtained
which can be processed quantitatively like single tracer autoradiograms.
The validity of the method for the investigation of local coupling of flow
and metabolism was tested under various physiological and
pathophysiological conditions. Coupling was tight in
barbiturate-anesthetized healthy animals, but not under halothane
anesthesia where uncoupling occurred in various subcortical structures.
Focal seizures induced by topical application of penicillin on the cortical
surface led to a coupled increase of metabolism and flow in thalamic relay
nuclei but not at the site of penicillin administration where increased
glucose utilization was not accompanied by similar increase in blood flow.
Both coupled and uncoupled increases in local glucose utilization were
observed in spreading depression and in circumscribed areas of experimental
brain tumors. The results obtained demonstrate that double tracer
autoradiography allows allows the very precise local assessment of cerebral
blood flow and glucose utilization, and, therefore, is particularly suited
to the study of regional coupling processes under various experimental
conditions.