Alterations of plasma and cerebrospinal fluid glutamate levels in rats treated with the N-methyl-D-aspartate receptor antagonist, ketamine.
It has been reported that the repeated administration of a sub-anesthetic dose of an N-methyl-D-aspartate receptor antagonist, ketamine, can produce an animal model of schizophrenia. Since no information is available on the alterations of the amino acid levels in ketamine-treated rats, we investigated the amino acid composition in the plasma and cerebrospinal fluid of rats that were repeatedly administered with ketamine for 5 consecutive days (30 mg/kg/day). The plasma and cerebrospinal fluid amino acid compositions in the fifth week after cessation of repeated ketamine administration were determined by highperformance liquid chromatography with fluorescence detection using a pre-column fluorescence reagent, i.e. 4-fluoro-7nitro-2,1,3-benzoxadiazole. Among the amino acids investigated in the present study, the level of plasma glutamic acid increased significantly (p < 0.05), while that of the cerebrospinal fluid glutamic acid decreased significantly in the ketamine-treated rats as compared with these levels in control rats injected with saline (p < 0.05, n = 7). These alterations in the glutamic acid level in the plasma and cerebrospinal fluid resemble those in schizophrenic patients, suggesting that ketamine-treated rats may be a useful model for performing research on the pathophysiology of schizophrenia.
Tomiya
Masayuki
M
Department of Analytical Chemistry, School of Pharmaceutical Sciences, University of Shizuoka, Japan.
Fukushima
Takeshi
T
Kawai
Junko
J
Aoyama
Chiaki
C
Mitsuhashi
Shogo
S
Santa
Tomofumi
T
Imai
Kazuhiro
K
Toyo'oka
Toshimasa
T
D000818:Animals; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology*; D018698:Glutamic Acid / Q000097:blood* / Q000134:cerebrospinal fluid*; D007649:Ketamine / Q000494:pharmacology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors*
D018691:Excitatory Amino Acid Antagonists; D016194:Receptors, N-Methyl-D-Aspartate; D018698:Glutamic Acid; D007649:Ketamine