by Kusayama T, Watanabe S
Department of Psychology,
Keio University, Tokyo, Japan.
Neuroreport 2000 Aug 3;11(11):2511-3
Reinforcing properties of dopamine agonist, methamphetamine, for planarians were examined with the conditioned place preference (CPP) procedure. The planarians showed preference for the environment associated with methamphetamine administration. This reinforcing effect was antagonized by pretreatment with non-selective dopamine antagonist, haloperidol. Both selective D1 antagonist SCH23390 and selective D2 antagonist sulpiride also blocked the reinforcing effect of methamphetamine. These results suggest that reinforcing effects of dopaminergic drugs can be traced back to invertebrates such as planarians.