Changes in dopamine and acetylcholine in striatum of the awake rat after chronic treatment with a dopamine uptake blocker.

The effects of chronic treatment with a dopamine uptake blocker on dopamine and acetylcholine extracellular concentrations in striatum of the awake rat was studied. Male Wistar rats received daily injections (i.p.) of the dopamine uptake blocker nomifensine (10 mg/kg) during 22 days. Control group was injected with vehicle (saline). Microdialysis experiments were performed on days 1, 8, 15 and 22 of treatment. Nomifensine injections increased extracellular concentration of dopamine in striatum in all days of treatment without differences among days. In contrast, acetylcholine levels showed no changes in days 1 and 8 but increased in days 15 and 22 of treatment. These results shows that chronic treatment with a dopamine uptake inhibitor, nomifensine, has no effects on dopamine release but it increases acetylcholine release in striatum of the awake rat. These results would help to further understand the effects of chronic dopamine uptake inhibition.