Brain P-gp and Inflammation in People With Epilepsy

Background: * The brain is protected by a barrier that keeps toxins in the blood from reaching the brain. However, this barrier can also keep useful medications from reaching the brain. P-glycoprotein (P-gp) is a brain protein that is part of the blood-brain barrier. The level of P-gp is higher in people with epilepsy than in people without epilepsy. These different levels of P-gp may explain why some people have seizures that do not respond well to medications. Researchers want to see if P-gp can affect the response to epilepsy medications. * Epilepsy may also be associated with brain inflammation. Researchers also want to look at the part of the brain affected by epilepsy to see if inflammation is present. Objectives: * To see if P-gp can affect the response to epilepsy medications. * To see if inflammation is present in the part of the brain affected by epilepsy. Eligibility: * \<TAB\>Individuals between 18 and 60 years of age who have temporal lobe epilepsy. We plan to study some patients whose seizures are well controlled by drugs, and some whose seizures are not controlled. * \<TAB\> * Healthy volunteers between 18 and 60 years of age. Design: * This study requires four or five visits to the NIH Clinical Center over the course of a year. The visits will be outpatient visits and will last from 2 to 5 hours. * Participants will be screened with a physical exam and medical history. Blood and urine samples will be collected. * All participants will have two positron emission tomography (PET) scans. The scans will take place during different visits. Different drugs will be used in each scan. One drug will be used to temporarily block the effect of P-gp in the brain. The other drug will show areas of inflammation in the brain. * Participants with epilepsy will have a third PET scan. This scan will also look at P-gp activity in the brain. However, it will not use the drug that blocks the effect of P-gp. * All participants will also have one magnetic resonance imaging scan. This scan will help show brain function.