300 - 
200 - 
100 - 
0 
INTACT SHAM DLF 
TREATMENT GROUP 
FIGURE 1 1 . Effects of DLF lesions on noxious stimulus-evoked “pain" 
behaviors and on overall FLI. Results are expressed as mean 
(±SEM, ordinate) behavioral AUC scores (top) or number of 
neurons per 50-pm section expressing FLI (bottom) in rats 
receiving either ICV saline (open bars) or DAMGO (0.60 pg; 
filled bars). DAMGO significantly inhibited both the pain- 
response and FLI expression in both intact and sham rats. 
These inhibitory effects were reversed in rats with DLF lesions. 
The mean response for DAMGO-treated intact animals was 
zero; this is indicated by + (top). ** Indicates groups significantly 
different from saline controls by either Dunnett’s (top) or 
Neuman-Keuls (bottom) post-hoc tests (p<0.01). 
SOURCE: Reprinted with permission from Neuroscience 42, Gogas, K.R.; 
Presley, R.W.; Levine, J.D.; and Basbaum, A.I. The antinociceptive 
action of supraspinal opioids results from an increase in descending, 
inhibitory control: Correlation of nociceptive behavior and c-fos 
expression, 1991, Pergamon Press, pic. 
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