Differential expression of two glutamate transporters, GLAST and GLT-1, in an experimental rat model of glaucoma.
Glutamate is the major excitatory neurotransmitter of the mammalian retina, and excessive glutamate has been implicated in the pathogenesis of glaucoma. It is well known that glutamate transport, mainly via GLAST and GLT-1, is cardinal mechanism for maintaining glutamate homeostasis in normal and pathological conditions, including ischemia in the brain. In an effort to understand the role of glutamate and the glutamate regulation system of the retina in the pathogenesis of glaucoma, we examined changes in the expression of two glutamate transporters, GLAST and GLT-1, by Western blot analysis and immunocytochemistry in a rat glaucoma model. GLT-1 was expressed in cone photoreceptors and some cone bipolar cells and the levels of expression were significantly increased in the cauterized eyes throughout the entire experimental period. In contrast, GLAST expression, which occurred in Müller cells, the main retinal glial cells, remained stable during the experimental period. These results suggest that GLT-1 may be a prerequisite for the maintenance of glutamate homeostasis in the retina undergoing glaucoma.
Park
Chan Kee
CK
Department of Ophthalmology, College of Medicine, The Catholic University of Korea, 505 Banpo-dong, Socho-gu, Seoul, 137-701, Korea.
Cha
Jiook
J
Park
Soo Chul
SC
Lee
Phil Young
PY
Kim
Jie Hyun
JH
Kim
Hwa Sun
HS
Kim
Shin Ae
SA
Kim
In-Beom
IB
Chun
Myung-Hoon
MH
D000704:Analysis of Variance; D000818:Animals; D015153:Blotting, Western; D002452:Cell Count; D004195:Disease Models, Animal; D027341:Excitatory Amino Acid Transporter 1 / Q000378:metabolism*; D027342:Excitatory Amino Acid Transporter 2 / Q000378:metabolism*; D005901:Glaucoma / Q000378:metabolism*; D007150:Immunohistochemistry; D007429:Intraocular Pressure; D009457:Neuroglia / Q000378:metabolism; D009798:Ocular Hypertension; D051381:Rats; D017207:Rats, Sprague-Dawley; D012160:Retina / Q000378:metabolism*; D051245:Retinal Bipolar Cells / Q000378:metabolism; D017949:Retinal Cone Photoreceptor Cells / Q000378:metabolism; D013997:Time Factors
D027341:Excitatory Amino Acid Transporter 1; D027342:Excitatory Amino Acid Transporter 2; C493392:Slc1a3 protein, rat