Isoflurane suppresses stress-enhanced fear learning in a rodent model of post-traumatic stress disorder.
Anesthesiology
; 110(3): 487-95, 2009 Mar.
Article
in En
| MEDLINE
| ID: mdl-19212264
ABSTRACT
BACKGROUND:
A minority of patients who experience awareness and/or pain during surgery subsequently develop post-traumatic stress disorder. In a rodent model of post-traumatic stress disorder, stress-enhanced fear learning (SEFL), rats are preexposed to a stressor of 15 foot shocks. Subsequent exposure to a single foot shock produces an enhanced fear response. This effect is akin to sensitized reactions shown by some post-traumatic stress disorder patients to cues previously associated with the traumatic event.METHODS:
The authors studied the effect of isoflurane and nitrous oxide on SEFL. Rats were exposed to the inhaled anesthetic during or after a 15-foot shock stressor. Then, rats were given a single foot shock in a different environment. Their fear response was quantified in response to the 15-foot shock and single-foot shock environments. SEFL longevity was tested by placing a 90-day period between the 15 foot shocks and the single foot shock. In addition, the intensity of the foot shock was increased to evaluate treatment effectiveness.RESULTS:
Increasing isoflurane concentrations decreased SEFL when given during, but not after, the stressor. At 0.40 minimum alveolar concentration (MAC), isoflurane given during the stressor blocked SEFL 90 days later. A threefold increase in the stressor intensity increased the isoflurane concentration required to block SEFL to no more than 0.67 MAC. As with isoflurane, nitrous oxide suppressed SEFL at a similar MAC fraction.CONCLUSIONS:
These results suggest that sufficient concentrations (perhaps 0.67 MAC or less) of an inhaled anesthetic may prevent SEFL.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Stress Disorders, Post-Traumatic
/
Stress, Psychological
/
Disease Models, Animal
/
Fear
/
Isoflurane
/
Learning
Type of study:
Etiology_studies
/
Prognostic_studies
Limits:
Animals
Language:
En
Journal:
Anesthesiology
Year:
2009
Document type:
Article
Affiliation country:
Estados Unidos