title: Effects of glucose load on brain extracellular lactate concentration in conscious rats using a microdialysis technique.
abstract: Changes in the brain lactate concentration in cerebral extracellular fluid (ECF) during intravenous infusion of glucose and local administration of glucose were investigated in adult, conscious, unrestrained rats, with a microdialysis probe in the posterior hippocampus. The rats were infused intravenously with either 25% sucrose solution or 25% glucose solution at a rate of 16.6 microliters.min-1.100 g-1 for three hours. The blood glucose concentration reached 17.0 +/- 2.6 mM at the end of the glucose infusion, and brain ECF glucose showed a parallel change with the blood glucose concentration and increased to 2.37 +/- 0.30 mM. However, blood and brain ECF glucose concentrations did not change in animals infused with the sucrose solution. On the other hand, the blood lactate concentration in the glucose-infused group also increased from 0.93 +/- 0.18 mM to 2.85 +/- 0.39 mM at the end of the glucose infusion, which was significantly higher than that measured in the sucrose-infused group. The blood lactate level in the glucose-infused group returned to the basal level by the end of the experiment. Brain ECF lactate concentrations increased from 1.21 +/- 0.06 mM to 1.69 +/- 0.11 mM in glucose-infused animals, but did not change in the sucrose-infused animals. The brain ECF lactate concentration showed a positive correlation with the brain ECF glucose concentration in glucose-infused animals. Another group of rats was administered glucose locally for 90 min after substitution of artificial cerebrospinal fluid.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Anesthesiology, Kyoto Prefectural University of Medicine, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Harada
authors.forename: T
authors.initials: T
authors.lastname: Sawa
authors.forename: C
authors.initials: C
authors.lastname: Okuda
authors.forename: T
authors.initials: T
authors.lastname: Matsuda
authors.forename: Y
authors.initials: Y
authors.lastname: Tanaka
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D003956:Dialysis; D005110:Extracellular Space / Q000378:metabolism*; D005947:Glucose / Q000494:pharmacology*; D007773:Lactates / Q000097:blood / Q000378:metabolism*; D019344:Lactic Acid; D008297:Male; D051381:Rats; D017208:Rats, Wistar
chemical_list: D001786:Blood Glucose; D007773:Lactates; D019344:Lactic Acid; D005947:Glucose