This study evaluates the usefulness of a PET radioligand to estimate the binding on the mGlu4 receptor in the brain. mGlu4 has been proposed as a therapeutic target in Parkinson's disease.

Inclusion Criteria:

• Healthy subjects age 20-50 inclusive
• Body mass index (BMI) between 19 and 30 kg/m2
• Normal sMRI scan, performed within 3 months, as judged by the investigator
• The subject is, in the opinion of the investigator, generally healthy based on assessment of medical history, physical examination, vital signs, ECG, and the results of the hematology, clinical chemistry, urinalysis, serology, and other laboratory tests
• Women of childbearing potential and men whose partner is of child bearing potential must be willing to ensure that they or their partner use effective contraception during the trial and for 3 months thereafter
• A propensity to tolerate confined spaces for prolonged periods
• Suitability for radial and/or brachial artery blood sampling and cannulation

Exclusion Criteria:

• History of clinically significant cardio-or cerebrovascular, pulmonary, renal, hepatic, neurological, mental or gastrointestinal disorder or any other major disorder that may interfere with the objectives of the study, as judged by the investigator
• The subject has 1 or more clinical laboratory test values outside the reference range, which in the opinion of the investigator are clinically significant
• Screening supine blood pressure >=140 mm Hg (systolic) or >=90 mm Hg (diastolic), following at least 5 minutes of supine rest. If blood pressure (BP) is >=140 mm Hg (systolic) or >=90 mm Hg (diastolic), the BP should be repeated two more times and the average of the three BP values should be used to determine the subject's eligibility
• The subject has a resting pulse <=50 or >=100 bpm at the Screening Visit
• The subject has a QTc interval >430 ms (Bazett's or Fridericia's correction) at the Screening Visit or at he Baseline Visit, as calculated by the ECG equipment and evaluated by the investigator. The ECG may be repeated if any of the values are out-of-range or abnormal
• The subject is pregnant or breastfeeding
• Habitual use of nicotine products and addictive substances
• Any finding of significance on MRI scans as judged by the investigator.
• Any previous PET measurements for scientific purposes
• Use of CNS active drugs and/or NSAIDs 1 month prior to the first PET examination
• The subject is exposed to significant level of ionizing radiation at work
• The subject has undergone any clinical procedures involving significant exposure to radiation (excluding dental X-ray and common X-rays of the chest or extremities)
• The subject has received radio labeled material less than 12