Metabolic responses in discrete regions of rat brain following acute administration of glutamate.
Glutamate is a major excitatory neurotransmitter in the mammalian brain. Nevertheless, high extracellular levels of this amino acid have been shown to be toxic to several neuronal populations, but no data are available to show how glutamate homeostasis is altered in response to local infusion of glutamate. In the present study, 1 microM of glutamate was stereotactically injected into cerebral cortex, striatum, and hippocampus of adult rat brain, and the activities of key metabolic enzymes, lactate dehydrogenase, glutamate dehydrogenase, aspartate aminotransferase, and alanine aminotransferase were evaluated by postmortem analysis in tissue homogenates. The results show that glutamate bolus, induced significant alterations in vivo glutamate and energy metabolism, as evidenced by marked alterations in these enzyme activities, whereas dizocilpine, a glutamate receptor antagonist, negated many of the effects induced by high glutamate. However, the degree of involvement of these observations in glutamate-induced neurotoxicity remains to be ascertained.
Bawari
Meenakshi
M
Department of Neurology, SGPG Institute of Medical Sciences, Lucknow, UP, 226014 India.
Babu
G Nagesh
GN
D000410:Alanine Transaminase / Q000378:metabolism; D000818:Animals; D001219:Aspartate Aminotransferases / Q000378:metabolism; D001921:Brain / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D002540:Cerebral Cortex / Q000187:drug effects / Q000201:enzymology; D003342:Corpus Striatum / Q000187:drug effects / Q000201:enzymology; D016291:Dizocilpine Maleate / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005969:Glutamate Dehydrogenase / Q000378:metabolism; D018698:Glutamic Acid / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D006624:Hippocampus / Q000187:drug effects / Q000201:enzymology; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008297:Male; D009928:Organ Specificity; D051381:Rats; D017208:Rats, Wistar
D018691:Excitatory Amino Acid Antagonists; D018698:Glutamic Acid; D016291:Dizocilpine Maleate; D007770:L-Lactate Dehydrogenase; D005969:Glutamate Dehydrogenase; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase