FIGURE 5. Increase in Fos immunoreactivity 2 hours after IP injection of 20 
mg/kg of GBR - 12909. As formulated in this study, GBR- 12909 
produced essentially the same increases in c-fos mRNA and Fos- 
immunoreactive proteins that cocaine did. However, behaviorally, 
the time course of GBR’s action was much longer than that of 
cocaine. This aspect was not systematically examined for its 
effect on immunocytochemical or molecular endpoints. GBR- 
12909 treatment caused marked staining throughout the rostral- 
caudal and dorso-ventral extent of the striatum as illustrated in 
the section through the posterior caudate. (64X magnification; 
antibody dilution, 1:10, 000) 
and in ventral striatal areas (figures 5 and 6). We also observed a marked 
increase in c -fos mRNA with GBR-1 2909 in striatum at the 20 mg/kg IP dose 
when rats were sacrificed within 30 to 40 minutes of injection (not shown). 
GBR-1 2909 was also effective when given intravenously: Increases in c -fos 
190 
