Glial glutamate transporter expression patterns in brains from multiple mammalian species.
It is generally assumed that rodent brains can be used as representative models of neurochemical function in other species, such as humans. We have compared the distributions of the predominant glial glutamate transporters in rodents, rabbits, cats, pigs, monkeys, and humans. We identify similarities but also significant differences between species. GLT-1v, which is abundantly expressed by rodent astrocytes, is expressed only in a rare subset of astrocytes of cats and humans, and appears to be absent from brains of rabbits and monkeys. Conversely, in the pig brain GLT-1v is expressed only by oligodendrocytes. GLAST and GLT-1alpha expression differed significantly between species; while rodents and rabbits exhibited uniform expression patterns in cortex, higher species, including cats, pigs, monkeys, and humans, exhibited heterogeneities in cortical and hippocampal expression. Patches devoid of labeling intermingling with patches of strong labeling were evident in areas such as temporal cortex and frontal cortex. In addition, we noted that in human motor cortex, there were inconsistencies in labeling for the C-terminal of GLT-1alpha and common domains of GLT-1, suggesting that the C-terminal region may be missing or that an unidentified splicing is present in many human astrocytes. Collectively our data suggest that assumptions as to the roles of glutamate transporters in any species may need to be tested empirically.
Williams
Susan M
SM
Department of Physiology and Pharmacology, School of Biomedical Sciences, University of Queensland, Brisbane, Australia.
Sullivan
Robert K P
RK
Scott
Heather L
HL
Finkelstein
David I
DI
Colditz
Paul B
PB
Lingwood
Barbara E
BE
Dodd
Peter R
PR
Pow
David V
DV
D000368:Aged; D027322:Amino Acid Transport System X-AG / Q000378:metabolism*; D000818:Animals; D001253:Astrocytes / Q000378:metabolism; D001921:Brain / Q000033:anatomy & histology / Q000378:metabolism*; D002144:Callithrix; D002415:Cats; D027342:Excitatory Amino Acid Transporter 2 / Q000378:metabolism*; D018698:Glutamic Acid / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D008322:Mammals / Q000033:anatomy & histology / Q000378:metabolism*; D051379:Mice; D008875:Middle Aged; D009457:Neuroglia / Q000378:metabolism*; D009836:Oligodendroglia / Q000378:metabolism; D020033:Protein Isoforms / Q000378:metabolism; D017434:Protein Structure, Tertiary / Q000502:physiology; D011817:Rabbits; D051381:Rats; D017208:Rats, Wistar; D013045:Species Specificity; D034421:Sus scrofa; D009435:Synaptic Transmission / Q000502:physiology
D027322:Amino Acid Transport System X-AG; D027342:Excitatory Amino Acid Transporter 2; D020033:Protein Isoforms; D018698:Glutamic Acid