Lowry, John P.
(2004)
Monitoring Real-time Metabolite Trafficking in the Brain using Microelectrochemical Biosensors.
MCFA Annals, 3.
pp. 92-97.
Abstract
In a first series of experiments a glucose oxidase-based
biosensor implanted in the striatum of freely moving rats
was used to determine the concentration of brain
extracellular (ECF) glucose in two distinct ways. With a
modification of the zero-net-flux method, in which
different concentrations of glucose are infused through a
dialysis probe glued to the biosensor, the concentration at
which there was no change in glucose current was
calculated by regression analysis; this gave an ECF
concentration of 351 ± 16 μM. The concentration
calculated from the basal current and the
in vitro
calibration of the biosensor was not significantly different
from this. The basal extracellular glucose concentration
determined by either method remained constant over a
period of several days. In a
second series of experiments
rats were implanted in the striatum with a Pt/Ir electrode
for measurement of regional cerebral blood flow (rCBF,
H
2
clearance technique), a carbon paste electrode for
monitoring tissue oxygen, and a glucose biosensor for
monitoring extracellular glucose. There was a parallel
increase in rCBF and oxygen in response to neuronal
activation (5 min tail pinch). During the neuronal
activation there was a decrease in ECF glucose which was
followed by a slow rise that took 30 min to return to basal
levels. Finally, a group of rats implanted with a combined
glucose biosensor and dialysis probe were given a 5 min
tail pinch while the dialysis probe was perfused with
either artificial cerebrospinal
fluid (aCSF) alone or aCSF
with the addition of the
β
-adrenoceptor antagonist
propranolol. Perfusion with aCSF once again produced an
initial reduction in extracellular glucose, which was co-
extensive with the period of stimulation, followed by a
delayed and long-lasting increase in glucose. Propranolol
had no effect on basal levels
of glucose but suppressed the
delayed increase. These results suggests that
extracellular
glucose in the brain is not derived directly from the blood
vascular system but from some other source which is
most likely to be astrocytes
| Item Type: |
Article
|
| Keywords: |
Real-time Metabolite Trafficking; Brain; Microelectrochemical Biosensors; |
| Academic Unit: |
Faculty of Science and Engineering > Chemistry |
| Item ID: |
8045 |
| Depositing User: |
John Lowry
|
| Date Deposited: |
22 Mar 2017 16:46 |
| Journal or Publication Title: |
MCFA Annals |
| Publisher: |
Marie Curie Fellowship Association |
| Refereed: |
Yes |
| Funders: |
Marie Curie Fellowship, Health Research Board (HRB), Enterprise Ireland (EI), NUI Maynooth, RSC/EPSRC, Wellcome Trust |
| URI: |
|
| Use Licence: |
This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available
here |
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