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Monoamine and amino acid levels in a rat brain subject to magnetic resonance imaging
S268 2503
DEVELOPMENT OF A NEW NIR MICROPROBE SYSTEM: ITS APPLICATION TO A STUDY OF THE VISUAL CORTEX. MUTSUJI TAKAHASHIl. HIROYUKI OKADAI, KAZUYUKI IMAMURA233, TSUYOSHI SHIOMITSU233, HIROTAKA ONOE273, HIDE0 TSUKADAl>z, YASUYOSHI WATANABE233, 1The 5th Research Groun. Central Research Laboratorv, Hamamatsu Photonics K.K.. 5000 Hirakuchi. Hamakita-Citv. 430 Janan, 2Subfemtomole Biorecoenition Proiect, JRDC. 3Neuroscience Division. Osaka Bioscience Institute. Furuedai 6-2-4, Suita_Citv. We have developed a new near infrared (NIR) spectrophotometry system with microprobes of optical transmitter and recievers. To estimate the subject region, an absorber was scanned three dimensionally around transmitter and reciever probes in vitro. The obtained profile showed two spindle-shaped regions beneath respective probes. Hb02 and Hb in the rat brain were changed as mirror images in compliance with the change in the concentration of oxygen in respiration gas. We applied this system to the visual cortex of adult cats which had been monocularly deprived throughout the sensitive period. Stimulation of the normal eye showed an increase of Hb02, while that of the deprived eye fail to induce the response. The results indicate that this system can be applied to measure the changes in the blood flow in a restricted brain region following neural stimulation.
2504
1NVITROPET:A NEW METHOD FORIMAGING NEURONAL FUNCTIONS IN LIVINGBRAIN SLICES. M193.m ONOE1.2. Hsl,2. C&&$ . $Ml,3 YGsuyosfil wATwl,z 1,~ w Prnipct *Resear h D v 1 m 565. lanan. 3Uo&a Universitv PET Centre. S-751 85 II&. Swea Using positron emitter labeled compounds and imaging plates, we developed a new in vitro method for imaging neuronal functions in brain slices, while they were kept in oxygenated Krebs-Ringer solution. Images of glucose metabolism were obtained by incubating the rat brain slices with [**F]fluoro-deoxyglucose (FDG) for 45 minute followed by 30 min wash. They were exposed to an imaging plate for 30 min. Scanning and analysis of the imaging plate revealed higher FDG uptake in the gray matter than in the white matter, suppression of FDC uptake either by tetrodotoxin treatment or by cooling to 1 “C, and enhancement of the uptake by incubation with 50 mM high K+ solution. In addition, there were a large regional variation of FDG uptake both in the normal and high K+ conditions. Incubation with [ilC]raclopride, a dopamine Dz receptor antagonist, revealed specific and high affinity binding sites in the caudate-putamen. Incubation with L[ilC]Dopa resulted in high accumulation of radioactivity in the striatum. The accumulated radioactivity decreased when they were exposed to 50 mM high K+ solution, probably reflecting release of [llC]dopamine from the striatal tissue. Due to short half-life of the radioactivity, multiple experiments in the same brain slice were possible. These results suggest that the present method, in vitro PET, could be used for imaging the metabolism, receptors, and uptake and release of neurotransmitters in the same living brain slices.
2505
MONOAMINE RESONANCE
Jlab. I Aaencztrial 305 JAPiQI
AND AMINO IMAGING.
ACID &QJI
LEVELS IN A RAT HYODO, mcs
Science
BRAIN
and Technoloav
SUBJECT TO MAGNETIC Div.. Mechanical Ena._ . *
.&Namlkl
l-2,
Tsukuba.
During the Magnetic Resonance Imaging (MRI), the subject is placed in a strong static magnetic field and a dynamic magnetic field. The subject is also irradiated by radio waves. To investigate the influence of Magnetic Resonance Imaging on brain metabolism, we monitored monoamine (dopamine (DA), dihydroxyphenyl acetic acid (DOPAC) etc) levels and amino acid levels using in vivo microdialysis. Spin-echo sequences and gradient-echo sequences were applied to 10 to 20 week old Wister rats by a 2 Tesla (20k gauss) MRI equipment. The rats were anesthetized by isoflurene and warm water was used to stabilize their body temperatures while monitoring. We monitored the monoamine and amino acid levels every ten minutes during the application of the MRI sequences for 2 hours. We found that these levels changed during the 2 hours, but the changes peculiar to the MRI sequences could not be distinguished from normal changes which may occur in the absence of the sequences. significant rapid influence was not detected by changes in monoamine and Therefore, amino acid levels in the rat's brains.
DEVELOPMENT OF A NEW NIR MICROPROBE SYSTEM: ITS APPLICATION TO A STUDY OF THE VISUAL CORTEX. MUTSUJI TAKAHASHIl. HIROYUKI OKADAI, KAZUYUKI IMAMURA233, TSUYOSHI SHIOMITSU233, HIROTAKA ONOE273, HIDE0 TSUKADAl>z, YASUYOSHI WATANABE233, 1The 5th Research Groun. Central Research Laboratorv, Hamamatsu Photonics K.K.. 5000 Hirakuchi. Hamakita-Citv. 430 Janan, 2Subfemtomole Biorecoenition Proiect, JRDC. 3Neuroscience Division. Osaka Bioscience Institute. Furuedai 6-2-4, Suita_Citv. We have developed a new near infrared (NIR) spectrophotometry system with microprobes of optical transmitter and recievers. To estimate the subject region, an absorber was scanned three dimensionally around transmitter and reciever probes in vitro. The obtained profile showed two spindle-shaped regions beneath respective probes. Hb02 and Hb in the rat brain were changed as mirror images in compliance with the change in the concentration of oxygen in respiration gas. We applied this system to the visual cortex of adult cats which had been monocularly deprived throughout the sensitive period. Stimulation of the normal eye showed an increase of Hb02, while that of the deprived eye fail to induce the response. The results indicate that this system can be applied to measure the changes in the blood flow in a restricted brain region following neural stimulation.
2504
1NVITROPET:A NEW METHOD FORIMAGING NEURONAL FUNCTIONS IN LIVINGBRAIN SLICES. M193.m ONOE1.2. Hsl,2. C&&$ . $Ml,3 YGsuyosfil wATwl,z 1,~ w Prnipct *Resear h D v 1 m 565. lanan. 3Uo&a Universitv PET Centre. S-751 85 II&. Swea Using positron emitter labeled compounds and imaging plates, we developed a new in vitro method for imaging neuronal functions in brain slices, while they were kept in oxygenated Krebs-Ringer solution. Images of glucose metabolism were obtained by incubating the rat brain slices with [**F]fluoro-deoxyglucose (FDG) for 45 minute followed by 30 min wash. They were exposed to an imaging plate for 30 min. Scanning and analysis of the imaging plate revealed higher FDG uptake in the gray matter than in the white matter, suppression of FDC uptake either by tetrodotoxin treatment or by cooling to 1 “C, and enhancement of the uptake by incubation with 50 mM high K+ solution. In addition, there were a large regional variation of FDG uptake both in the normal and high K+ conditions. Incubation with [ilC]raclopride, a dopamine Dz receptor antagonist, revealed specific and high affinity binding sites in the caudate-putamen. Incubation with L[ilC]Dopa resulted in high accumulation of radioactivity in the striatum. The accumulated radioactivity decreased when they were exposed to 50 mM high K+ solution, probably reflecting release of [llC]dopamine from the striatal tissue. Due to short half-life of the radioactivity, multiple experiments in the same brain slice were possible. These results suggest that the present method, in vitro PET, could be used for imaging the metabolism, receptors, and uptake and release of neurotransmitters in the same living brain slices.
2505
MONOAMINE RESONANCE
Jlab. I Aaencztrial 305 JAPiQI
AND AMINO IMAGING.
ACID &QJI
LEVELS IN A RAT HYODO, mcs
Science
BRAIN
and Technoloav
SUBJECT TO MAGNETIC Div.. Mechanical Ena._ . *
.&Namlkl
l-2,
Tsukuba.
During the Magnetic Resonance Imaging (MRI), the subject is placed in a strong static magnetic field and a dynamic magnetic field. The subject is also irradiated by radio waves. To investigate the influence of Magnetic Resonance Imaging on brain metabolism, we monitored monoamine (dopamine (DA), dihydroxyphenyl acetic acid (DOPAC) etc) levels and amino acid levels using in vivo microdialysis. Spin-echo sequences and gradient-echo sequences were applied to 10 to 20 week old Wister rats by a 2 Tesla (20k gauss) MRI equipment. The rats were anesthetized by isoflurene and warm water was used to stabilize their body temperatures while monitoring. We monitored the monoamine and amino acid levels every ten minutes during the application of the MRI sequences for 2 hours. We found that these levels changed during the 2 hours, but the changes peculiar to the MRI sequences could not be distinguished from normal changes which may occur in the absence of the sequences. significant rapid influence was not detected by changes in monoamine and Therefore, amino acid levels in the rat's brains.