TY - JOUR
T1 - Translocation of glutamate transporter subtype excitatory amino acid carrier 1 protein in kainic acid-induced rat epilepsy
AU - Furuta, Akiko
AU - Noda, Mami
AU - Suzuki, Satoshi O.
AU - Goto, Yoshinobu
AU - Kanahori, Yoshiko
AU - Rothstein, Jeffrey D.
AU - Iwaki, Toru
N1 - Funding Information:
Supported by the Ministry of Education, Culture, Sports, Science, and Technology [grant-in-aid for scientific research (C) no. 13680824 ] and the Clinical Research Foundation (1999) of Japan.
PY - 2003/8/1
Y1 - 2003/8/1
N2 - Glutamate excitotoxicity has been implicated in the pathophysiology of epilepsy. Systemic injection of kainic acid (KA) in the rat produces an animal model of human temporal lobe epilepsy. We examined the temporal expression of the sodium-dependent neuronal glutamate transporter, excitatory amino acid carrier 1 (EAAC1), in KA-induced rat epilepsy. As an early alteration, perinuclear deposits of EAAC1 protein were found mainly in the large pyramidal neurons at the hippocampus, neocortex, piriform cortex, and amygdala with the reduction of neuropil staining 6 hours after KA injection. Immunoelectron microscopic study revealed that the perinuclear EAAC1 immunoreactivity corresponded to the translocation to the Golgi complex. At this time point, EAAC1 mRNA was down-regulated. The intracellular aggregation of EAAC1 primarily disappeared by 24 hours. In vitro studies indicated that internalization of EAAC1 from the plasma membrane to the intracellular compartment by KA treatment was associated with the reduction of electrogenic transporter currents. Our results suggest that the transient EAAC1 internalization participates in the modulation of the transporter function preventing excessive glutamate uptake to pyramidal neurons during the early stage of epilepsy.
AB - Glutamate excitotoxicity has been implicated in the pathophysiology of epilepsy. Systemic injection of kainic acid (KA) in the rat produces an animal model of human temporal lobe epilepsy. We examined the temporal expression of the sodium-dependent neuronal glutamate transporter, excitatory amino acid carrier 1 (EAAC1), in KA-induced rat epilepsy. As an early alteration, perinuclear deposits of EAAC1 protein were found mainly in the large pyramidal neurons at the hippocampus, neocortex, piriform cortex, and amygdala with the reduction of neuropil staining 6 hours after KA injection. Immunoelectron microscopic study revealed that the perinuclear EAAC1 immunoreactivity corresponded to the translocation to the Golgi complex. At this time point, EAAC1 mRNA was down-regulated. The intracellular aggregation of EAAC1 primarily disappeared by 24 hours. In vitro studies indicated that internalization of EAAC1 from the plasma membrane to the intracellular compartment by KA treatment was associated with the reduction of electrogenic transporter currents. Our results suggest that the transient EAAC1 internalization participates in the modulation of the transporter function preventing excessive glutamate uptake to pyramidal neurons during the early stage of epilepsy.
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U2 - 10.1016/S0002-9440(10)63705-4
DO - 10.1016/S0002-9440(10)63705-4
M3 - Article
C2 - 12875997
AN - SCOPUS:0042345032
SN - 0002-9440
VL - 163
SP - 779
EP - 787
JO - American Journal of Pathology
JF - American Journal of Pathology
IS - 2
ER -