To evaluate the following items by PET examination in Japanese heathy adult male subjects who received single oral administration of TS-091 in an unblinded manner.

1. Relationship between plasma concentration and H3 receptor-occupancy of TS-091
2. Time course changes in H3 receptor-occupancy of TS-091

Inclusion Criteria:

Subjects who met all of the following criteria.

• Age: between ≥20 years and <40 years at the time of providing written consent for participation in the study.
• Body mass index (BMI): ≥18.5 and <25.0 on the day of screening test.
• Subject who received a prior explanation on the study and was able to understand its content and capable of providing voluntary written consent for participation in the study.
• Other protocol defined inclusion criteria could apply-

Exclusion Criteria:

Subjects who came under any of the following exclusion criteria.

• Subjects who were considered to have some disease and not healthy by the investigator or subinvestigator according to his medical judgment based on the results of screening test
• Subjects with a drug or food allergy or a history thereof.
• Subjects with a significant allergic disposition (e.g. asthma requiring treatment) or a history thereof.
• Subjects with a history of heparin-induced thrombocytopenia.
• Other protocol defined exclusion criteria could apply