Parkinson's disease (PD) is characterized by a degeneration of nigrostriatal dopaminergic neurons that results in a hypercholinergic state in the striatum. This hypercholinergic state contributes to the clinical signs of PD. However, the mechanisms that underlie this state remain unknown. Cholinergic interneurons (ChIs) are the main source of acetylcholine in the striatum. Many studies have highlighted the importance of their normal physiological activity to guarantee a normal motor control and goal-directed behaviour. Moreover, recent studies with optogenetic and chemogenetic approaches have shown that reducing ChIs activity ameliorates parkinsonian symptoms and modifies L-dopa induced dyskinesia in PD animal models. Here, we review the described alterations in ChIs physiology that may contribute to a hypercholinergic state in PD. The best-established finding is an increase of ChIs intrinsic membrane excitability after dopaminergic denervation of striatum. Understanding the molecular basis of ChIs dysfunction in PD could help to develop new therapeutic tools to restore their normal activity and decrease parkinsonian symptoms, improving life quality of PD patients.
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bioRxiv
December 2024
Department of Medical Neurobiology, Institute of Medical Research Israel - Canada, Faculty of the Medicine, The Hebrew University of Jerusalem, Jerusalem, 9112102, Israel.
Striatal cholinergic interneurons (CINs) activate nicotinic acetylcholine receptors on dopamine axons to extend the range of dopamine release. Here we show that synchronous activation of CINs induces and extends the range of local serotonin release via a similar mechanism. This process is exaggerated in the hypercholinergic striatum of a mouse model of OCD-like behavior, implicating CINs as critical regulators of serotonin levels in the healthy and pathological striatum.
View Article and Find Full Text PDFNeurobiol Dis
July 2023
Neuro Division, Clinical Neurosciences Department, Stockholm, Sweden. Electronic address:
Background And Objectives: It has been recently suggested that LRRK2 mutations are associated with a more benign clinical phenotype and a potentially more preserved cholinergic function in Parkinson's disease (PD). However, to our knowledge, no studies have tested whether the better clinical progression observed in LRRK2-PD patients is associated with more preserved volumes of a cholinergic brain area, the basal forebrain (BF). To address this hypothesis, here we compared BF volumes in LRRK2 carriers with and without PD with respect to idiopathic PD (iPD) patients and controls, and assessed whether they are associated with better clinical progression observed in LRRK2-PD compared to iPD.
View Article and Find Full Text PDFJ Neurochem
April 2024
Faculty of Pharmacy, Department of Pharmacology and Toxicology, Comenius University Bratislava, Bratislava, Slovakia.
The α7 nicotinic receptors (NR) have been confirmed in the heart but their role in cardiac functions has been contradictory. To address these contradictory findings, we analyzed cardiac functions in α7 NR knockout mice (α7) in vivo and ex vivo in isolated hearts. A standard limb leads electrocardiogram was used, and the pressure curves were recorded in vivo, in Arteria carotis and in the left ventricle, or ex vivo, in the left ventricle of the spontaneously beating isolated hearts perfused following Langedorff's method.
View Article and Find Full Text PDFLancet Neurol
April 2022
VA Geriatric Research Education and Clinical Center, Ann Arbor, MI, USA; Department of Neurology, University of Michigan, Ann Arbor, MI, USA.
In patients with Parkinson's disease, heterogeneous cholinergic system changes can occur in different brain regions. These changes correlate with a range of clinical features, both motor and non-motor, that are refractory to dopaminergic therapy, and can be conceptualised within a systems-level framework in which nodal deficits can produce circuit dysfunctions. The topographies of cholinergic changes overlap with neural circuitries involved in sleep and cognitive, motor, visuo-auditory perceptual, and autonomic functions.
View Article and Find Full Text PDFMed Sci Monit
December 2021
Second Clinical Medical College, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, China (mainland).
BACKGROUND Major depressive disorder (MDD) is the leading cause of disability around the world. It is generally agreed that the central cholinergic system plays an important role in emotional regulation. Acetylcholine (ACh) is now a new target for antidepressants.
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