Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
A-B. Relative changes in oxygen levels in the NAc and SC space induced by fentanyl at 20 (A) and 60 μg/kg doses (B). Filled symbols mark values significantly different (p<0.05) from pre-injection baseline. C-D. Changes in oxygen levels (C-NAc; D-SC space) following iv injections of naloxone or saline (time=600 s) 10 minutes after iv injection of fentanyl at 60 μg/kg (time= 0 s). Asterisks show intervals where between-group differences were significant (p<0.05).
