Expression of a glutamate transporter subtype, EAAT4, in the developing human cerebellum.
A glutamate transporter subtype, EAAT4, is closely related to removal of glutamate from the synaptic cleft. Immunohistochemistry for EAAT4 demonstrated the specific distribution and localization of its expression in the developing human cerebellum. Purkinje cells showed faint EAAT4 immunostaining at 17 gestational weeks (GW), which became increasingly intense from 23 GW to the infantile period. In the late fetal to early infantile periods, Purkinje cells showed marked immunoreactivity. After the late infantile period, EAAT4 immunoreactivity was the same in extent as in the adult pattern. Its intracellular localization also changed with development. EAAT4 immunoreactivity was demonstrated in the short processes of Purkinje cells in the early embryonic period, in the cell bodies and dendrites in the late fetal to early infantile periods, and then in the spines after the late infantile period. In the adult cerebellum, immunoreactivity was detected strongly in the spines of Purkinje cells and weakly in the cell bodies. No immunoreactivity was found in the axons or axon terminals of the cells. Thus, the glutamate transporter exhibits developmental changes in its distribution in the cerebellum and its localization in Purkinje cells. EAAT4 immunoreactivity may be related to the dendritic arborization of cells in the molecular layer.
Itoh
M
M
Department of Mental Retardation and Birth Defect Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan. itoh@ncnaxp.ncnp.go.jp
Watanabe
Y
Y
Watanabe
M
M
Tanaka
K
K
Wada
K
K
Takashima
S
S
D000293:Adolescent; D000328:Adult; D027322:Amino Acid Transport System X-AG; D002531:Cerebellum / Q000737:chemistry* / Q000196:embryology / Q000254:growth & development; D002648:Child; D002675:Child, Preschool; D018118:Chloride Channels / Q000032:analysis*; D005314:Embryonic and Fetal Development / Q000502:physiology; D050581:Excitatory Amino Acid Transporter 4; D005260:Female; D005865:Gestational Age; D050491:Glutamate Plasma Membrane Transport Proteins; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D007223:Infant; D008297:Male; D008875:Middle Aged; D017470:Receptors, Glutamate / Q000032:analysis*; D027981:Symporters
D027322:Amino Acid Transport System X-AG; D018118:Chloride Channels; D050581:Excitatory Amino Acid Transporter 4; D050491:Glutamate Plasma Membrane Transport Proteins; D017470:Receptors, Glutamate; C493391:SLC1A6 protein, human; D027981:Symporters