Confounding effects of volatile anesthesia on CBV assessment in rodent forebrain following ethanol challenge.
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.
Luo
Feng
F
Experimental Imaging Abbott Laboratories, Abbott Park, Illinois 60064, USA. Feng.Luo@abbott.com
Li
Zhixin
Z
Treistman
Steven N
SN
Kim
Young Ro
YR
King
Jean A
JA
Fox
Gerard B
GB
Ferris
Craig F
CF
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
D000431:Ethanol