title: Measurement of glucose metabolism in rat spinal cord slices with dynamic positron autoradiography.
abstract: We attempted to measure the regional metabolic rate of glucose (MRglc) in sliced spinal cords in vitro. The thoracic spinal cord of a mature Wister rat was cut into 400-mum slices in oxygenated and cooled (1-4 degrees C) Krebs-Ringer solution. After at least 60 min of preincubation, the spinal cord slices were transferred into double polystyrene chambers and incubated in Krebs-Ringer solution at 36 degrees C, bubbled with 5% O(2)/5% CO(2) gas. To measure MRglc, we used the dynamic positron autoradiography technique (dPAT) with F-18-2-fluoro-2-deoxy-d-glucose ([(18)F]FDG) and the net influx constant of [(18)F]FDG as an index. Uptake curves of [(18)F]FDG were well fitted by straight lines for more than 7 h after the slicing of the spinal cord (linear regression coefficient, r=0.99), indicating a constant uptake of glucose by the spinal cord tissue. The slope (K), which denotes MRglc, is affected by tetrodotoxin, and high K(+) (50 mM) or Ca(2+)-free, high Mg(2+) solution. After 10 min of hypoxia, the K value following reoxygenation was similar to the unloaded control value, but after 45 min of hypoxia, the K value was markedly lower than the unloaded control value, and after >90 min of reoxygenation it was nearly 0. Our results indicate that the living spinal cord slices used retained an activity-dependent metabolism to some extent. This technique may provide a new approach for measuring MRglc in sliced living spinal cord tissue in vitro and for quantifying the dynamic changes in MRglc in response to various interventions such as hypoxia.
authors.affiliation: Department of Cardiovascular Surgery, Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangzhou, China.
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Fan
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Asai
authors.forename: Koichi
authors.initials: K
authors.lastname: Morioka
authors.forename: Kenzo
authors.initials: K
authors.lastname: Uchida
authors.forename: Hisatoshi
authors.initials: H
authors.lastname: Baba
authors.forename: Kuniyoshi
authors.initials: K
authors.lastname: Tanaka
authors.forename: Jian
authors.initials: J
authors.lastname: Zhuang
authors.forename: Hidehiko
authors.initials: H
authors.lastname: Okazawa
authors.forename: Yasuhisa
authors.initials: Y
authors.lastname: Fujibayashi
mesh_terms: D000818:Animals; D001345:Autoradiography / Q000379:methods*; D001921:Brain / Q000378:metabolism; D019788:Fluorodeoxyglucose F18; D005947:Glucose / Q000378:metabolism*; D000860:Hypoxia / Q000378:metabolism; D008297:Male; D019275:Radiopharmaceuticals; D051381:Rats; D017208:Rats, Wistar; D013116:Spinal Cord / Q000378:metabolism*; D013779:Tetrodotoxin / Q000494:pharmacology
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D013779:Tetrodotoxin; D005947:Glucose