Blocking Receptor Binding clinical trials

Specific PET Radioligand Binding to Translocator Protein

Background: - A brain protein called translocator protein (TSPO) shows changes in some brain diseases. A radioactive drug called 11C-(R)-PK 11195 is used to take pictures of TSPO using a camera called positron emission tomography (PET). Researchers want to find out how well 11C-(R)-PK 11195 takes the pictures. Objective: - To evaluate the radioactive chemical 11C-(R)-PK 11195. Eligibility: - Healthy volunteers ages 18-55. Design: - Participants will be screened with a medical exam. - Participants will have scans at up to 4 visits. - PET scan using 11C-(R)-PK 11195: - A small tube (catheter) will be put into an artery at the wrist or elbow, by a needle. The needle will be removed, leaving only the catheter in the artery. Blood samples will be taken through this catheter. - Another catheter will be placed into a vein in the arm or hand. - 11C-(R)-PK 11195 will be injected through the second catheter. - The PET scanner is shaped like a doughnut. Participants will lie on a bed that slides in and out of it. They may get a plastic mask for their face and head. - Participants will receive a dose of emapunil by mouth. Participants will then have another PET scan. - Participants may have a magnetic resonance imaging (MRI) scan. The MRI scanner is a metal cylinder surrounded by a magnetic field. The participant will lie on a table that can slide in and out of the cylinder. Participants will get earplugs for the loud knocking noises. - After each scan, participants will get a follow-up phone call. Two to seven days after taking emapunil, participants will return for a follow-up visit.