I2PETPG - Imidazoline2 Binding Sites in a Group of Participants Diagnosed With AD
Status:
Terminated
Trial end date:
2017-07-01
Target enrollment:
Participant gender:
Summary
The imdazoline2 binding site (I2BS) is known to reside inside astrocytes. Changes in the
numbers of I2BS in post mortem tissue has implicated them in a range of psychiatric
conditions such as depression and addiction, along with neurodegenerative disorders such as
Alzheimer's disease and Huntington's chorea. Preclinical studies have also demonstrated
functional interactions with the opioid system, where I2BS ligands have been shown to affect
tolerance to morphine and alleviate some of the morphine withdrawal syndrome in rats.
Recently the I2BS and I2BS ligands have been shown to have some interesting analgesic effects
in different models of pain.
The location of I2BS on astrocytic glial cells and the possibility that they may in some way
regulate glial fibrillary acidic protein have led to increased interest into the role of I2BS
and I2BS ligands in conditions characterised by marked gliosis. The number of I2BS has been
shown to increase in Alzheimer's disease post mortem, and it has also been suggested that
I2BS may be a marker for the severity and malignancy of human glioblastomas.
The lack of suitable imaging tools for the I2BS has meant that information regarding the
number and distribution of I2BS in the brain has come from preclinical species and in vitro
post-mortem studies. The recent development of [11C]BU99008 as a suitable PET ligand to
quantify I2BS in vivo, enables the direct quantification of I2BS availability and regional
distribution in the living human brain. In this study the investigators plan to utilise
[11C]BU99008 to quantify the regional brain availability of I2BS in the human brain in vivo
using PET.