title: NTP and PCr responses to hypoxia by hypothermic and normothermic respiring, superfused, neonatal rat cerebrocortical slices: an NMR spectroscopy study at 14.1 Tesla.
abstract: Although mechanisms of hypothermic neuroprotection during oxygen deprivation have long been investigated, further characterizations of various molecular mechanisms are appropriate. Anticipating future studies of hypothermia and hypoxia/ischemia, we investigated the extent to which our ex vivo, NMR-based, superfused brain slice model might be helpful. (Slices are approximately 350 microm thick, with 18 slices per 8 mm NMR tube.) 31P NMR spectroscopic measurements were made of hypothermia-induced changes in high energy phosphates, while simultaneously monitoring and controlling tissue temperature, using 1H NMR, the high spectroscopic resolution available at 14.1 Tesla (600 MHz for protons), and a recently published protocol. NTP and PCr concentrations in healthy, well-oxygenated slices decreased to (55 +/- 15)% and (66 +/- 30)% of their respective values at 28.0 degrees C when warmed to 38.0 degrees C, in approximate agreement with earlier in vivo studies by others. During 30 min hypoxia NTP and PCr decreased to non-observable values, regardless of temperature. After reoxygenation, NTP and PCr recoveries as percentages of respective prehypoxia values were (63% +/- 16%; 70%) +/- 5%) for hypothermic slices (28.0 degrees C), and (46% +/- 13%; 41% +/- hypothermic neuroprotection during oxygen deprivation in this model, which appears suitable for use in further studies.
authors.affiliation: Department of Anesthesia, University of California, San Francisco, San Francisco, California 94143-0648, USA.
authors.forename: L
authors.initials: L
authors.lastname: Litt
authors.forename: K
authors.initials: K
authors.lastname: Hirai
authors.forename: V J
authors.initials: VJ
authors.lastname: Basus
authors.forename: T L
authors.initials: TL
authors.lastname: James
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002540:Cerebral Cortex / Q000378:metabolism*; D003080:Cold Temperature; D000860:Hypoxia / Q000378:metabolism*; D066298:In Vitro Techniques; D009682:Magnetic Resonance Spectroscopy; D009711:Nucleotides / Q000378:metabolism*; D010101:Oxygen Consumption; D010477:Perfusion; D010710:Phosphates / Q000378:metabolism*; D010725:Phosphocreatine / Q000378:metabolism*; D011522:Protons; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D009711:Nucleotides; D010710:Phosphates; D011522:Protons; D010725:Phosphocreatine