Age, Sex and Smoking Influence Opioid Receptor Function in the Brain


Opioids regulate the feelings of pleasure and pain in the brain. A study by the national Turku PET Centre shows that age, sex and smoking influence μ-opioid receptor density in the brain. The results of the study help to better understand the differences between individuals when it comes to neuropsychiatric disorders.

Dysfunctions of the brain’s opioid system are associated with several disorders, such as addiction, and chronic pain problems.

– We noticed in our study that age, sex and smoking have fundamental influence on the organisation of the human brain’s opioid system. This suggests that there are significant differences in the opioid system between individuals, which may explain why some individuals are prone to develop opioid-linked pathological states, such as psychiatric disorders, explains Tatu Kantonen, Doctor of Medicine.

Brain’s μ-opioid receptors act as important mediators for body’s own opioids in the brain. This study analysed positron emission tomography (PET) brain scans targeting μ-opioid receptors from 204 individuals with no neurologic or psychiatric disorders. This database was compiled with new computational tools developed at the Turku PET Centre.

aivokuva opioidijärjestelmästä

Image: Distribution of μ-opioid receptors in the human brain. Warmer colour stands for more receptors, and colder colour for less receptors. The original image has been published in the NeuroImage.


The study is based on the AIVO database hosted by Turku University Hospital and Turku PET Centre. The database contains different in vivo molecular brain scans for extensive analyses.

The results have been published in the esteemed NeuroImage journal.

More Information:

Tatu Kantonen, Doctor of Medicine, Doctoral Candidate, Turku PET Centre, University of Turku, +358 50 4911870,

Lauri Nummenmaa, Professor, Turku PET Centre, University of Turku, +358 50 574 7933,

Created 28.05.2020 | Updated 28.05.2020