title: Resistance of brain glucose metabolism to thiopental-induced CNS depression in newborn piglets.
abstract: The transition from mild sedation to deep anaesthesia is marked by the phenomenon of burst suppression (BS). FDG-PET studies show that the cerebral metabolic rate for glucose (CMRglc) declines dramatically with onset of BS in the adult brain. Global CMRglc increases substantially in the post-natal period and achieves its maximum in preadolescence. However, the impact of post-natal brain development on the vulnerability of CMRglc to the onset of BS has not been documented. Therefore, cerebral blood flow and metabolism were measured using a variant of the Kety-Schmidt method, in conjunction with quantitative regional estimation of brain glucose uptake by FDG-PET in groups of neonate and juvenile pigs, under a condition of light sedation or after induction of deep anaesthesia with thiopental. Quantification of simultaneous ECoG recordings was used to establish the correlation between anaesthesia-related changes in brain electrical activity and the observed cerebrometabolic changes. In the condition of light sedation the magnitude of CMRglc was approximately 20% higher in the older pigs, with the greatest developmental increase evident in the cerebral cortex and basal ganglia (P<0.05). Onset of BS was associated with 20-40% declines in CMRglc. Subtraction of the mean parametric maps for CMRglc showed the absolute reductions in CMRglc evoked by thiopental anaesthesia to be two-fold greater in the pre-adolescent pigs than in the neonates (P<0.05). Thus, the lesser suppression of brain energy demand of neonate brain during deep anaesthesia represents a reduced part of thiopental suppressing brain metabolism in neonates.
authors.affiliation: Institute of Molecular Cell Biology, Jena University Hospital, Friedrich Schiller University, Jena, Germany.
authors.forename: Bernd
authors.initials: B
authors.lastname: Walter
authors.forename: Michael
authors.initials: M
authors.lastname: Eiselt
authors.forename: Paul
authors.initials: P
authors.lastname: Cumming
authors.forename: Guoming
authors.initials: G
authors.lastname: Xiong
authors.forename: Rainer
authors.initials: R
authors.lastname: Hinz
authors.forename: Susanne
authors.initials: S
authors.lastname: Uthe
authors.forename: Peter
authors.initials: P
authors.lastname: Brust
authors.forename: Reinhard
authors.initials: R
authors.lastname: Bauer
mesh_terms: D018686:Anesthetics, Intravenous / Q000494:pharmacology*; D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000000981:diagnostic imaging / Q000187:drug effects / Q000378:metabolism*; D001931:Brain Mapping; D002560:Cerebrovascular Circulation / Q000187:drug effects* / Q000502:physiology; D005947:Glucose / Q000378:metabolism*; D011877:Radionuclide Imaging; D013552:Swine; D013874:Thiopental / Q000494:pharmacology*
chemical_list: D018686:Anesthetics, Intravenous; D005947:Glucose; D013874:Thiopental