FIGURE 4. Increase in striatal Fos immunoreactivity after cocaine treatment. 
Dense nuclear staining can be seen for Fos-immunoreactive 
proteins at 2 hours after IP injection of 30 mg/kg cocaine. The 
lateral ventricle is on the right. (64X magnification; antibody 
dilution, 1:10,000) 
number of cells recruited was not that much greater, the intensity of staining 
increased dramatically. The degree of staining intensity throughout the 
affected regions went from light brown to darker brown to nearly black in 
many cells as the dose of cocaine or GBR-1 2909 increased. The intensity 
aspect was not quantitated and does not reproduce well in the black and white 
photomicrographs but can be readily appreciated in the tissue sections. GBR- 
12909 was also capable of increasing Fos protein content in caudate nucleus 
189 
