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Title: Effect of metabolic alterations on the accumulation of technetium-99m-labeled d, l-HMPAO in slices of rat cerebral cortex

Abstract

It is widely recognized that the distribution of technetium-99m-labeled d,l-hexamethylpropylene amine oxime ({sup 99m}Tc-HMPAO) in the brain is determined by the regional blood flow. However, other factors may affect this process including the metabolism of the brain tissue. To examine this possibility we studied the effects of metabolic alterations on {sup 99m}Tc-HMPAO uptake in rat brain cortex slices, with concurrent measurement of oxygen consumption (QO{sub 2}). {sup 99m}Tc-HMPAO uptake was determined by incubating slices of rat cerebral cortex at 37{degrees}C in Krebs-Ringer phosphate glucose medium containing {sup 99m}Tc-HMPAO with and without test substances. Differential gradients for {sup 99m}Tc activity between the tissue and the suspending medium (T/M ratio) were derived from the equation T/M[{sup 99m}Tc] = counts per gram of tissue/counts per milliliter of medium. The QO{sub 2} of the brain slices was measured using a biological oxygen monitor equipped with a polarographic oxygen probe. Inhibitors affecting oxidative phosphorylation caused parallel suppression of the T/M ratio and QO{sub 2}. Agents that uncouple oxidation from phosphorylation increased the QO{sub 2} and decreased the T/M ratio. Incubation of slices at 22{degrees}C depressed the T/M ratio and QO{sub 2}. The presence of inhibitors of oxidative phosphorylation in the incubation medium increased the releasemore » of {sup 99m}Tc activity from slices that had been prelabeled with {sup 99m}Tc-HMPAO. These findings suggest that the altered metabolic status of the brain tissue modulates the kinetics and net accumulation of {sup 99m}Tc-HMPAO at the cellular level by either depressing uptake, increasing back-diffusion, or both. 33 refs., 4 figs., 3 tabs.« less

Authors:
; ; ;  [1]
  1. Virginia Medical Center, Brockton, VA (United States)|[Harvard Medical School, Boston, MA (United States)
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
54861
Resource Type:
Journal Article
Journal Name:
Journal of Cerebral Blood Flow and Metabolism
Additional Journal Information:
Journal Volume: 14; Journal Issue: 2; Other Information: PBD: Mar 1994
Country of Publication:
United States
Language:
English
Subject:
55 BIOLOGY AND MEDICINE, BASIC STUDIES; CEREBRAL CORTEX; METABOLISM; TECHNETIUM 99; BIOLOGICAL ACCUMULATION; OXYGEN; CONSUMPTION RATES; RATS; TRACER TECHNIQUES; TISSUE EXTRACTS; PHOSPHORYLATION

Citation Formats

Ahn, C.S., Tow, D.E., Yu, C.C., and Greene, R.W. Effect of metabolic alterations on the accumulation of technetium-99m-labeled d, l-HMPAO in slices of rat cerebral cortex. United States: N. p., 1994. Web. doi:10.1038/jcbfm.1994.39.
Ahn, C.S., Tow, D.E., Yu, C.C., & Greene, R.W. Effect of metabolic alterations on the accumulation of technetium-99m-labeled d, l-HMPAO in slices of rat cerebral cortex. United States. doi:10.1038/jcbfm.1994.39.
Ahn, C.S., Tow, D.E., Yu, C.C., and Greene, R.W. Tue . "Effect of metabolic alterations on the accumulation of technetium-99m-labeled d, l-HMPAO in slices of rat cerebral cortex". United States. doi:10.1038/jcbfm.1994.39.
@article{osti_54861,
title = {Effect of metabolic alterations on the accumulation of technetium-99m-labeled d, l-HMPAO in slices of rat cerebral cortex},
author = {Ahn, C.S. and Tow, D.E. and Yu, C.C. and Greene, R.W.},
abstractNote = {It is widely recognized that the distribution of technetium-99m-labeled d,l-hexamethylpropylene amine oxime ({sup 99m}Tc-HMPAO) in the brain is determined by the regional blood flow. However, other factors may affect this process including the metabolism of the brain tissue. To examine this possibility we studied the effects of metabolic alterations on {sup 99m}Tc-HMPAO uptake in rat brain cortex slices, with concurrent measurement of oxygen consumption (QO{sub 2}). {sup 99m}Tc-HMPAO uptake was determined by incubating slices of rat cerebral cortex at 37{degrees}C in Krebs-Ringer phosphate glucose medium containing {sup 99m}Tc-HMPAO with and without test substances. Differential gradients for {sup 99m}Tc activity between the tissue and the suspending medium (T/M ratio) were derived from the equation T/M[{sup 99m}Tc] = counts per gram of tissue/counts per milliliter of medium. The QO{sub 2} of the brain slices was measured using a biological oxygen monitor equipped with a polarographic oxygen probe. Inhibitors affecting oxidative phosphorylation caused parallel suppression of the T/M ratio and QO{sub 2}. Agents that uncouple oxidation from phosphorylation increased the QO{sub 2} and decreased the T/M ratio. Incubation of slices at 22{degrees}C depressed the T/M ratio and QO{sub 2}. The presence of inhibitors of oxidative phosphorylation in the incubation medium increased the release of {sup 99m}Tc activity from slices that had been prelabeled with {sup 99m}Tc-HMPAO. These findings suggest that the altered metabolic status of the brain tissue modulates the kinetics and net accumulation of {sup 99m}Tc-HMPAO at the cellular level by either depressing uptake, increasing back-diffusion, or both. 33 refs., 4 figs., 3 tabs.},
doi = {10.1038/jcbfm.1994.39},
journal = {Journal of Cerebral Blood Flow and Metabolism},
number = 2,
volume = 14,
place = {United States},
year = {1994},
month = {3}
}