Type 1 cannabinoid receptors in Parkinson’s disease: A Positron emission tomography study using the [18F]FMPEP-d2 Radioligand
Year: 2026
Type: dissertation
Study design: Observational Study
Abstract: Parkinson’s disease (PD) is a common neurodegenerative disorder. It is considered to be multifactorial, with dopaminergic deficits being the hallmark of the disease. It is clinically characterised by a combination of motor symptoms—including bradykinesia, rigidity, resting tremor, postural instability, and gait disturbances—as well as a broad range of non-motor manifestations, including cognitive impairment, mood disorders, autonomic dysfunction, and sleep disturbances. The diversity of these symptoms reflects the widespread neurobiological alterations underlying PD pathophysiology. The endocannabinoid system (ECS) is a neuromodulatory signalling system that is less studied in PD. The ECS regulates synaptic transmission, neuronal plasticity, and brain network activity. Type 1 cannabinoid (CB1) receptors are highly expressed in the basal ganglia, making them an interesting study target in basal ganglia disorders such as PD. This thesis investigated the availability of CB1 receptors in PD with positron emission tomography (PET) and the [18F]FMPEP-d2 tracer. Furthermore, the relationship between CB1 receptor availability and motor and cognitive symptoms of PD was studied. The results suggest that PD patients have lower CB1 receptor availability than healthy controls. However, dopaminergic medication increases CB1 receptor availability toward normal levels in PD. Furthermore, decreased CB1 receptor availability in PD is associated with postural instability and gait problems, as well as rigidity, but not with tremor or bradykinesia. Additionally, more impaired episodic memory and executive functioning in PD is associated with lower CB1 receptor availability. In conclusion, these findings suggest that alterations in ECS signalling are associated with the pathophysiology of PD and may contribute to the manifestation of certain motor and cognitive symptoms.
Source: UTUPub (University of Turku)
Author: Ajalin, Riikka
Language: English
Subfield: Pharmacology (medical)
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W7220797791