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Enhancing effect of MS-153, a neuroprotective agent, on glutamate uptake through GLT-1, a glial glutamate transporter
s91
ENHANCING EFFECT OF MS-153, A NEUROPROTECI’IVE AGENT, THROUGH GLT-1, A GLIAL GLUTAMATE TRANSPORTER
094
FUMIKI SHIMADA,
YASUHITO
Lab. of Mol. Pharmacol.,
SHIRAI,
OSAMU MORIKAWA
AND NAOAKl
ON GLUTAMATE
UPTAKE
SAITO
Biosignal Res. Ctr., Kobe Univ., Kobe 657-8501
MS-153, a novel cerebroprotective agent, has been reported to reduce the area of cerebral infarction and to minimize neurological deficits in an ischemic animal model. We previously demonstrated, using rat hippocampal slice, the inhibitory effect of MS-153 on glutamate efflux induced by K+-deporalization and by ischemia, aglycemia and hypoxia. The glutamate efflux is counterbalanced by the glutamate release from nerve ending and by glutamate uptake into the surrounding glial and neuronal cells. Ln particular, the glutamate uptake through glial glutamate transporter, GLT-1 plays an important role in the regulation of extracellular glutamate concentration. In the present study, to elucidate the mechanism of the inhibitory effect of MS-153 on glutamate efflux, we investigated the effect of MS-153 on [3H] glutamate uptake through GLT-1, Na+/K+dependent glial glutamate transporter, expressed in COS-7 cell. Pretreatment with MS-153 enhanced [3H] glutamate uptake through GLT-1 in a concentration-dependent between 1 and 100 PM, while the simultaneous treatment with MS-153 during glutamate uptake did not affected on GLT-1 activity. In contrast, [3H] GABA uptake through Na+/Cl--dependent GABA transporters was not influenced by MS-153. Ln addition, MS-153 had no effect on the activity of Na+/l(+-ATPase. These findings suggest that the reduction of the extracellular glutamate concentration may be attributed to the acceleration of glutamate uptake through glial glutamate transporter. DIFFERENTIAL TRANSPORTER ISCHEMIA
095
EXPRESSIONS OF GLYCINE mRNAS IN THE HIPPOCAMPUS
HIROKO FUJITA, KOHJI SATO, MASAHIRO
TRANSPORTER 1 AND THREE OF GERBILS WITH TRANSIENT
SAKANAKA
Dept. of Second Anatomy, Sch. of Medicine, Ehime Univ., Shigenobu,
Ehime 791-0295
Transient global ischemia leads to delayed cell death of pyramidal plays an crucial role in this process. NMDA receptor
of glycine transporter
the gerbil hippocampus in astrocytes
following
concentrations
(GLYTl)
neurons in the hippocampal
in harmony
in the ischemic
and three glutamate transporter
with degeneration
CA1 field. Glutamate
of glutamate and its co-agonist
3-min ischemia. GLYTl mRNA was transiently
in close vicinity to CA1 pyramidal neurons.
4th day after ischemia expressed
The extracellular
may be under the control of amino acid transpoters
temporal expressions
GLUTAMATE FOREBRAIN
brain. We invesitigated (EAACl,
up-regulated
GLAST
the spatial and
GLAST, GLTl) mRNAs in
and GLTl
in glial cells of the dentate gyrus and CA3 field but not in the CA1 field.These
binding to
at the 2nd day after ischemia
EAACl mR!NA in CA1 pyramidal neurons of the CA1 neurons.
glycine
started to decrease at the mRNAs
findings
were intensely
suggest
that GLYTI,
GLAST and GLTl are involved in neuronal death or survival in the ischemic hippocampus.
096 Takaaki Ah’,
Molecular cloning and characterization transports thyroid hormones Masayuki Kakyol,
of a multi-specific
Taro Tokui3, Hiroyuki Sakagami’.
organic anion transporter subtype which
Toshiyuki Nishio’,
Hisatake Kondo2. and
Hiromu Yawo 1 lDepa.rtment of Neurophysiology.
lDepartment
3Analytical and Metabolic Research Laboratories.
of Histology,
Tohoku University
Sankyo Co.. Ltd.. Tokyo,
School of Medicine. Sendai. 9X0-8575
140
A novel complimentary DNA for a new organic anion transporter subtype, OATP-RI (Genbank accession # U95011). which transports thyroid hormones as well as taurocholate was isolated through polymerase chain reaction-mediated DNA amplification and by the subsequent screening of a rat retina cDNA library. OATP-Rl consists of 662 amino acid residues and exhibits a structural architecture common to the organic anion transporter family, possessing the 12 putative membranespanning segments. The oocytes injected with OATP-RI cRNA showed uptake of taurocholate in a saturation manner. The cRNA injected oocytes also showed sodium-independent uptake of thyroid hormones, thyroxine and triiodothyronine. Northern blot and in situ analyses showed that the OATP-Rl messenger RNA was widely expressed in neuronal cells of the central nervous system (especially hippocampus and cerebellum). retina and choroid plexus. Hence. OATP-Rl appears to be responsible for transporting thq?oid hormones from circulation to neural cells. The OATP-RI mRNA wa\ also expressed in the liver. OATP-RI may have another physiological function of transporting thyroid hormones and organic anions in the liver.
ENHANCING EFFECT OF MS-153, A NEUROPROTECI’IVE AGENT, THROUGH GLT-1, A GLIAL GLUTAMATE TRANSPORTER
094
FUMIKI SHIMADA,
YASUHITO
Lab. of Mol. Pharmacol.,
SHIRAI,
OSAMU MORIKAWA
AND NAOAKl
ON GLUTAMATE
UPTAKE
SAITO
Biosignal Res. Ctr., Kobe Univ., Kobe 657-8501
MS-153, a novel cerebroprotective agent, has been reported to reduce the area of cerebral infarction and to minimize neurological deficits in an ischemic animal model. We previously demonstrated, using rat hippocampal slice, the inhibitory effect of MS-153 on glutamate efflux induced by K+-deporalization and by ischemia, aglycemia and hypoxia. The glutamate efflux is counterbalanced by the glutamate release from nerve ending and by glutamate uptake into the surrounding glial and neuronal cells. Ln particular, the glutamate uptake through glial glutamate transporter, GLT-1 plays an important role in the regulation of extracellular glutamate concentration. In the present study, to elucidate the mechanism of the inhibitory effect of MS-153 on glutamate efflux, we investigated the effect of MS-153 on [3H] glutamate uptake through GLT-1, Na+/K+dependent glial glutamate transporter, expressed in COS-7 cell. Pretreatment with MS-153 enhanced [3H] glutamate uptake through GLT-1 in a concentration-dependent between 1 and 100 PM, while the simultaneous treatment with MS-153 during glutamate uptake did not affected on GLT-1 activity. In contrast, [3H] GABA uptake through Na+/Cl--dependent GABA transporters was not influenced by MS-153. Ln addition, MS-153 had no effect on the activity of Na+/l(+-ATPase. These findings suggest that the reduction of the extracellular glutamate concentration may be attributed to the acceleration of glutamate uptake through glial glutamate transporter. DIFFERENTIAL TRANSPORTER ISCHEMIA
095
EXPRESSIONS OF GLYCINE mRNAS IN THE HIPPOCAMPUS
HIROKO FUJITA, KOHJI SATO, MASAHIRO
TRANSPORTER 1 AND THREE OF GERBILS WITH TRANSIENT
SAKANAKA
Dept. of Second Anatomy, Sch. of Medicine, Ehime Univ., Shigenobu,
Ehime 791-0295
Transient global ischemia leads to delayed cell death of pyramidal plays an crucial role in this process. NMDA receptor
of glycine transporter
the gerbil hippocampus in astrocytes
following
concentrations
(GLYTl)
neurons in the hippocampal
in harmony
in the ischemic
and three glutamate transporter
with degeneration
CA1 field. Glutamate
of glutamate and its co-agonist
3-min ischemia. GLYTl mRNA was transiently
in close vicinity to CA1 pyramidal neurons.
4th day after ischemia expressed
The extracellular
may be under the control of amino acid transpoters
temporal expressions
GLUTAMATE FOREBRAIN
brain. We invesitigated (EAACl,
up-regulated
GLAST
the spatial and
GLAST, GLTl) mRNAs in
and GLTl
in glial cells of the dentate gyrus and CA3 field but not in the CA1 field.These
binding to
at the 2nd day after ischemia
EAACl mR!NA in CA1 pyramidal neurons of the CA1 neurons.
glycine
started to decrease at the mRNAs
findings
were intensely
suggest
that GLYTI,
GLAST and GLTl are involved in neuronal death or survival in the ischemic hippocampus.
096 Takaaki Ah’,
Molecular cloning and characterization transports thyroid hormones Masayuki Kakyol,
of a multi-specific
Taro Tokui3, Hiroyuki Sakagami’.
organic anion transporter subtype which
Toshiyuki Nishio’,
Hisatake Kondo2. and
Hiromu Yawo 1 lDepa.rtment of Neurophysiology.
lDepartment
3Analytical and Metabolic Research Laboratories.
of Histology,
Tohoku University
Sankyo Co.. Ltd.. Tokyo,
School of Medicine. Sendai. 9X0-8575
140
A novel complimentary DNA for a new organic anion transporter subtype, OATP-RI (Genbank accession # U95011). which transports thyroid hormones as well as taurocholate was isolated through polymerase chain reaction-mediated DNA amplification and by the subsequent screening of a rat retina cDNA library. OATP-Rl consists of 662 amino acid residues and exhibits a structural architecture common to the organic anion transporter family, possessing the 12 putative membranespanning segments. The oocytes injected with OATP-RI cRNA showed uptake of taurocholate in a saturation manner. The cRNA injected oocytes also showed sodium-independent uptake of thyroid hormones, thyroxine and triiodothyronine. Northern blot and in situ analyses showed that the OATP-Rl messenger RNA was widely expressed in neuronal cells of the central nervous system (especially hippocampus and cerebellum). retina and choroid plexus. Hence. OATP-Rl appears to be responsible for transporting thq?oid hormones from circulation to neural cells. The OATP-RI mRNA wa\ also expressed in the liver. OATP-RI may have another physiological function of transporting thyroid hormones and organic anions in the liver.