title: Confounding effects of volatile anesthesia on CBV assessment in rodent forebrain following ethanol challenge.
abstract: OBJECTIVE
  To compare and contrast the pattern and characteristics of the cerebral blood volume (CBV) response to ethanol (EtOH) in rats under awake and anesthetized conditions.
  
  
  METHODS
  Acute EtOH (0.75 g/kg) challenge-induced CBV changes were measured using a contrast-enhanced functional MRI CBV method in 15 male Sprague Dawley rats under three experimental conditions: 1.0% to 1.2% isoflurane (N = 5); 0.8% halothane (N = 5); and awake with no anesthetic (N = 5). Physiological parameters were collected from bench settings in nine rats from the above different conditions. Four parameters: 1) area under the curve (AUC%); 2) the maximum signal change (Max%); 3) EtOH absorption rate (alpha(2)); and 4) EtOH elimination rate (alpha(1)) were employed to compare EtOH-induced MRI signals between the awake and anesthetized groups.
  
  
  RESULTS
  Both awake and anesthetized animals responded with an increase in CBV to EtOH challenge. However, the presence of anesthesia promoted a significant preferential flow to subcortical areas not seen in the awake condition.
  
  
  CONCLUSIONS
  Unclear mechanisms of anesthesia add a layer of uncertainty to the already complex interpretation of EtOH's influence on neuronal activity, cellular metabolism, and hemodynamic coupling.
authors.affiliation: Experimental Imaging Abbott Laboratories, Abbott Park, Illinois 60064, USA. Feng.Luo@abbott.com
authors.forename: Feng
authors.initials: F
authors.lastname: Luo
authors.forename: Zhixin
authors.initials: Z
authors.lastname: Li
authors.forename: Steven N
authors.initials: SN
authors.lastname: Treistman
authors.forename: Young Ro
authors.initials: YR
authors.lastname: Kim
authors.forename: Jean A
authors.initials: JA
authors.lastname: King
authors.forename: Gerard B
authors.initials: GB
authors.lastname: Fox
authors.forename: Craig F
authors.initials: CF
authors.lastname: Ferris
mesh_terms: D000758:Anesthesia; D000776:Anesthesiology / Q000379:methods; D000818:Animals; D019540:Area Under Curve; D001810:Blood Volume; D002540:Cerebral Cortex / Q000473:pathology; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D000431:Ethanol / Q000494:pharmacology; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D009474:Neurons / Q000473:pathology; D016548:Prosencephalon / Q000473:pathology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
chemical_list: D000431:Ethanol