Intracranial self-stimulation and locomotor traces as indicators for evaluating and developing antipsychotic drugs.

When chlorpromazine (CPZ) and lithium chloride (LiCl) are compared, the former suppresses both rat's intracranial self-stimulation (ICSS) and methamphetamine (MAP)-induced hyperactivity. On the other hand, the latter suppresses only MAP-induced abnormal hyperactivity but hardly suppresses a purpose-oriented ICSS associated with the reward system. Therefore, LiCl inhibits abnormal hyperactivity induced by MAP, but it does not suppress physiological motivation. Using the two types of antipsychotic drugs, the authors propose a method of combining the ICSS and locomotor activity together with its traces. These proposals are useful indicators for evaluating and developing the new antipsychotic drugs which are used clinically for psychotic patients and for understanding the drug-induced akinesia and anhedonia.