PK11195

PK11195 is a synthetic molecule. It belongs to a class of molecules called ligands, which can bind to receptors found on cells thereby transmitting various signals.

General information
PK11195 is an isoquinoline carboxamide which binds selectively to the peripheral benzodiazepine receptor (PBR). It is the most commonly used PBR ligand due to its high affinity for the PBR in all species.

Early autoradiographic studies using tritiated PK11195 ([3H]-PK11195) demonstrated that in the central nervous system (CNS) of rodent, it binds primarily to the ependymal walls, choroid plexus, and olfactory bulb. However, in the injured nervous system there is a robust and widespread increase in [3H]-PK11195 binding. The binding sites have since been determined to be on glial cells, including microglia, astrocytes, and infiltrating macrophages. The binding of [3H]-PK11195 is considered to be a useful tool in the assessment of neuronal damage.

In addition to being a marker of neuronal damage in animal models of CNS damage, PK11195 has been used successfully with human brain imaging techniques. [11C](R)-PK11195 has been used in positron emission tomography (PET) scanning to visualize brain inflammation in patients with neuronal damage. Increases in [11C](R)-PK11195 binding have been reported in patients with stroke, traumatic brain injury and in patients with chronic neurodegenerative conditions including Alzheimer's disease and Parkinson's disease.