2.5 mg/kg 
FIGURE 5. Camera lucida drawings of representative L4-L5 sections showing 
a dose-related, naloxone-reversible inhibition of formalin-evoked 
Fos-like immunoreactivity (FLI) by morphine. The labeling in the 
ventral gray matter is profoundly suppressed by 2.5 mg/kg; at any 
given dose, the region with the most residual staining is the 
superficial dorsal horn. 
SOURCE: Presley et al. 1 990. Copyright 1 990 by the Society for 
Neuroscience (New York). 
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