Speaker
Dr
Oleg Blagosklonov
(University of Franche-Comte and Jean Minjoz University Hospital, Besançon, France)
Description
Isotope studies provide valuable data about an organ’s function in vivo. Thanks to
positron emission tomography (PET) using the radiolabeled natural metabolites, such
as [18F]-2-fluoro-deoxy-d-glucose (FDG), biological and physiological meaning of
nuclear medicine scans has been considerably increased. Moreover, the higher
spatial resolution of PET scans allows the direct assessment of metabolism even in
small animals. Therefore it is of interest to elucidate the possibilities of the
technique in a study of some natural metabolites like glycine influencing the blood
microcirculation.
As a medicine glycine was recently shown to have a positive therapeutical effect in
the treatment of patients with ischemic stroke and some other neurological
disorders based on vascular disturbances. By previous direct biomicroscopic
investigations of pial microvessels in laboratory rats an expressed vasodilatory
effect of topically applied glycine was proved. The aim of this study was to
evaluate an influence of glycine on cerebral blood flow (CBF) in rat using FDG-PET
scan.
A baseline study was started immediately after IV injection of 19 MBq of FDG in a
rat anesthetized with ketamine and xylazine. The PET images were acquired twice,
one by one during 20 min. Two hours later, after sublingual application of glycine
(200 mg) and the second FDG injection, the pair of PET scan was performed during 20
min as well. Finally, 4 days after the first studies, we repeated the PET scans in
the same conditions after sublingual application of glycine (200 mg). The
quantitative analysis of FDG volume concentration (Bq/ml) in the rat brain was
performed based on maximum, minimum, mean and standard deviation values comparison
(e.soft software, Siemens, Germany).
The quantitative analysis demonstrated that, in two studies after glycine
administration, FDG volume concentration in the brain increased at least 1.5 times
in comparison with the baseline data. Moreover, the peak of FDG volume
concentration in the brain was coming in more rapidly. In fact, after glycine
dosing, this peak was observed in the scans performed immediately after FDG
injection and not in the second scan seen in the baseline study.
These results confirm enhancing effect of glycine on the rat CBF possibly because
of its vasodilatory effect on brain microvessels. Therefore, FDG-PET technique
contributes to better understanding of glycine pharmacokinetics and its positive
influence on brain blood supply. Further studies involving microPET technique and
radiolabeled glycine are needed for following up the fate of this natural
metabolite in vivo condition.
Author
Dr
Oleg Blagosklonov
(University of Franche-Comte and Jean Minjoz University Hospital, Besançon, France)
Co-authors
Prof.
Guennady Podoprigora
(Institute of Cytochemistry and Molecular Pharmacology, Moscow, Russia)
Dr
Hatem Boulahdour
(University of Franche-Comte and Jean Minjoz University Hospital, Besançon, France)
Prof.
Jean-Claude Cardot
(University of Franche-Comte and Jean Minjoz University Hospital, Besançon, France)
Mr
Laurent Comas
(University of Franche-Comte and Jean Minjoz University Hospital, Besançon, France)
Dr
Siamak Davani
(University of Franche-Comte and Jean Minjoz University Hospital, Besançon, France)
Dr
Yaroslav Nartsissov
(Institute of Cytochemistry and Molecular Pharmacology, Moscow, Russia)