“Chronic … of cocaine HCl (10 mg/kg, IP, every 12 hours for 10 … days) resulted in a significantly decreased rate of accumulation of 3,4-dihydroxyphenylalanine following decarboxylase inhibition (-27 to -33%) and of homovanillic acid following probenecid treatment (-25 to -34%) in rat striatum, limbic forebrain and midbrain.”