Novel PET radioligand shows potential to assess Alzheimer’s, Parkinson’s

A radiopharmaceutical tool developed by German and Swiss scientists has the potential to guide and assess treatment of neurological diseases like Alzheimer’s, Parkinson’s and multiple sclerosis with PET imaging.

The PET radioligand, known as C-Me-NB1 to co-creator Simon M. Ametamey, PhD, and his colleagues, was developed for imaging a specific class of glutamate receptors known as NMDA receptors in nerve cells, according to research published in the Journal of Nuclear Medicine. Medications that block NMDA receptors are common and prescribed for illnesses from depression to neuropathic pain to ischemic stroke, since activating the receptors can trigger an influx of calcium that can lead to cell death.

“The significance of the work lies in the fact that we have for the first time developed a useful PET radioligand that can be applied to image the GluN2B receptor subunit of the NMDA receptor complex in humans,” Ametamey said in a release from the Society of Nuclear Medicine and Molecular Imaging. “The availability of such a PET radioligand would not only help to better understand the role of NMDA receptors in the pathophysiology of the many brain diseases in which the NMDA receptor is implicated, but it would also help to select appropriate doses of clinically relevant GluN2B receptor candidate drugs.” 

In Ametamey et al.’s study, which measured the dose and effectiveness of NMDA receptor eliprodil via PET scans in live rats, found the receptors were fully occupied at neuroprotective doses of eliprodil. 

“These results mean that a new radiopharmaceutical tool is now available for studying brain disorders,” Ametamey said. “It joins the list of existing PET radiopharmaceuticals used in imaging studies to investigate and understand underlying causes of these brain disorders. Furthermore, future imaging studies using this new radioligand would throw more light on the involvement of NMDA receptors, specifically the GluN2B receptors, in normal physiological processes such as learning and memory.”