The purpose of the study is to assess the safety and tolerability of AZD2066 and to explore the effect of a single dose of AZD2066 on the function of the cardia (the opening between the stomach and the esophagus) compared to placebo (not containing any medical substance) in healthy volunteers.

Inclusion Criteria:

• Provision of written consent prior to any study specific procedures.
• Healthy subjects, age 18-45 years inclusive. Females must be of no childbearing potential or must use a highly effective contraceptive method.
• Clinically normal physical findings and laboratory values at the time of pre-entry visit, as judged by the investigator.

Exclusion Criteria:

• Clinically significant illness within the 2 weeks prior to the first dose of the investigational product, including a suspected/manifested infection according to WHO risk categories 2, 3 or 4, as judged by the investigator.
• A measured LES pressure of < 5mm Hg.
• History of previous or ongoing psychiatric disease/condition.