News | November 02, 2012

Caffeine’s Effect on Brain’s Adenosine Receptors Visualized for First Time

Scans allow researchers to study link between caffeine and neurodegenerative disorders

November 2, 2012 – Molecular imaging with positron emission tomography (PET) has enabled scientists for the first time to visualize binding sites of caffeine in the living human brain to explore possible positive and negative effects of caffeine consumption. According to research published in the November issue of The Journal of Nuclear Medicine, PET imaging with F-18-8-cyclopentyl-3-(3-fluoropropyl)-1-propylxanthine (F-18-CPFPX) shows that repeated intake of caffeinated beverages throughout a day results in up to 50 percent occupancy of the brain’s A1 adenosine receptors.

“The effects of caffeine to the human body are generally attributed to the cerebral adenosine receptors. In the human brain the A1 adenosine receptor is the most abundant,” said David Elmenhorst, M.D., lead author of “Caffeine Occupancy of Human Cerebral A1 Adenosine Receptors: In Vivo Quantification with F-18-CPFPX and PET.” “In vitro studies have shown that commonly consumed quantities of caffeine have led to a high A1 adenosine occupancy. Our study aimed to measure the A1 adenosine receptor occupancy with in vivo imaging.”

Fifteen male volunteers participated in the study. They abstained from caffeine intake for 36 hours and then underwent a PET scan with F-18-CPFPX. Caffeine was then introduced in short intravenous infusions, increasing in amount. To estimate the occupancy of A1 adenosine receptors by caffeine, the distribution volume at the baseline period of the PET scan was compared with the distribution volume after caffeine administration. Researchers determined that the concentration of the caffeine that displaces 50 percent of the binding of F-18-CPFPX to the A1 adenosine receptor was 13 mg/L, or approximately four to five cups of coffee.

An important finding of the study is that in most regular coffee drinkers, about half of the A1adenosine receptors may be occupied by caffeine. It is likely that this blockage of a substantial amount of cerebral A1 adenosine receptors will result in adaptive changes and lead to chronic alterations of receptor express and availability.

“There is substantial evidence that caffeine is protective against neurodegenerative diseases like Parkinson’s or Alzheimer’s disease,” noted Elmenhorst. “Several investigations show that moderate coffee consumption of three to five cups per day at mid-life is linked to a reduced risk of dementia in late life. The present study provides evidence that typical caffeine doses result in a high A1adenosine receptor occupancy and supports the view that the A1 adenosine receptor deserves broader attention in the context of neurodegenerative disorders.”

Caffeine is the most commonly consumed psychoactive substance worldwide and an active ingredient in innumerable food and beverages. Eighty percent of U.S. adults consume caffeine every day; the average for adults is 200 mg of caffeine per day (two 5-ounce cups of coffee or four sodas). It affects an individual’s alertness, attention, cognitive performance, as well as reduces sleepiness.

Authors of the article “Caffeine Occupancy of Human Cerebral A1 Adenosine Receptors: In Vivo Quantification with 18F-CPFPX and PET” include David Elmenhorst, Andres Matusch and Oliver H. Winz, Institute of Neuroscience and Medicine (INM-2), Forschungszentrum Juelich, Juelich, Germany; Phillip T. Meyer, Institute of Neuroscience and Medicine (INM-2), Forschungszentrum Juelich, Juelich, Germany and Department of Nuclear Medicine, University Hospital, Freiburg, Freiburg, Germany; and Andreas Bauer, Institute of Neuroscience and Medicine (INM-2), Forschungszentrum Juelich, Juelich, Germany and Department of Neurology, Medical Faculty, Heinrich-Heine-University Duesseldorf, Duesseldorf, Germany.

For more information: www.snmmi.org

Related Content

Amazon Comprehend Medical Brings Medical Language Processing to Healthcare
News | Artificial Intelligence | February 15, 2019
Amazon recently announced Amazon Comprehend Medical, a new HIPAA-eligible machine learning service that allows...
Study Assesses Risk of MRI Exams for Patients With Tattoos
News | Magnetic Resonance Imaging (MRI) | February 01, 2019
A new European study concluded that magnetic resonance imaging (MRI) exams pose little risk for people with tattoos,...
Stereotactic Radiotherapy Improves Long-Term Survival in Stage-IV Cancers
News | Stereotactic Body Radiation Therapy (SBRT) | January 31, 2019
The first report from a phase II, multi-center clinical trial indicates stereotactic radiation can extend long-term...
ImaginAb Enrolls First Patient in Phase II PET Agent Clinical Trial
News | Radiopharmaceuticals and Tracers | January 30, 2019
ImaginAb Inc. announced the enrollment of the first patient in the Phase II clinical trial of the company’s CD8+ T Cell...
Artificial Intelligence Research Receives RSNA Margulis Award
News | Digital Radiography (DR) | January 28, 2019
The Radiological Society of North America (RSNA) presented its seventh Alexander R. Margulis Award for Scientific...
FDA Clears United Imaging Healthcare uExplorer Total-Body Scanner
Technology | PET-CT | January 23, 2019
January 23, 2019 — United Imaging Healthcare (United Imaging) announced U.S.
 Artificial Intelligence Shows Potential for Triaging Chest X-rays
News | Digital Radiography (DR) | January 23, 2019
An artificial intelligence (AI) system can interpret and prioritize abnormal chest X-rays with critical findings,...
Novel Technique May Significantly Reduce Breast Biopsies
News | Breast Biopsy Systems | January 17, 2019
A novel technique that uses mammography to determine the biological tissue composition of a tumor could help reduce...
Digital Mammography Increases Breast Cancer Detection
News | Mammography | January 16, 2019
The shift from film to digital mammography increased the detection of breast cancer by 14 percent overall in the United...