Fig. 5.

Effects of scopolamine (A) and/or GBR12909 (B) on dopamine concentration in the striatal ECF of the monkey brain. A microdialysis probe was inserted into the striatal region via the guide cannula. The probe was perfused with Krebs'–Henseleit solution (pH 7.4) at a rate of 5 μl/min. Samples were collected every 15 min, and the content of dopamine was measured by HPLC with electrochemical detection. The averaged data obtained from 0 to 120 min without any infusion were used as baseline data. Saline or scopolamine at doses of 10 or 100 μg/kg was administered 120 min after the start of sampling (arrow with S). GBR12909 at a dose of 0.5 mg/kg was administered 30 min after saline or scopolamine administration (arrow with G). The striatal ECF dopamine level was expressed as percentage of baseline.