In vivo microdialysis in Parkinson's research

Unraveling the Neural Circuits: Techniques, Opportunities and Challenges in Epilepsy Research

Epilepsy, a prevalent neurological disorder characterized by high morbidity, frequent recurrence, and potential drug resistance, profoundly affects millions of people globally. Understanding the microscopic mechanisms underlying seizures is crucial for effective epilepsy treatment, and a thorough understanding of the intricate neural circuits underlying epilepsy is vital for the development of targeted therapies and the enhancement of clinical outcomes. This review begins with an exploration of the historical evolution of techniques used in studying neural circuits related to epilepsy. It then provides an extensive overview of diverse techniques employed in this domain, discussing their fundamental principles, strengths, limitations, as well as their application. Additionally, the synthesis of multiple techniques to unveil the complexity of neural circuits is summarized. Finally, this review also presents targeted drug therapies associated with epileptic neural circuits. By providing a critical assessment of methodologies used in the study of epileptic neural circuits, this review seeks to enhance the understanding of these techniques, stimulate innovative approaches for unraveling epilepsy's complexities, and ultimately facilitate improved treatment and clinical translation for epilepsy.

Basal and Evoked Neurotransmitter Levels in Parkin, DJ-1, PINK1 and LRRK2 Knockout Rat Striatum

Parkinson's disease (PD) is the most common neurodegenerative movement disorder and is characterized by the loss of neurons in the substantia nigra that project to the striatum and release dopamine (DA), which is required for normal movement. Common non-motor symptoms likely involve abnormalities with other neurotransmitters, such as serotonin, norepinephrine, acetylcholine, glycine, glutamate and gamma-aminobutyric acid (GABA). As part of a broad effort to provide better PD research tools, the Michael J. Fox Foundation for Parkinson's Research funded the generation and characterization of knockout (KO) rats for genes with PD-linked mutations, including PINK1, Parkin, DJ-1 and LRRK2. Here we extend the phenotypic characterization of these lines of KO rats to include in vivo microdialysis to measure both basal and potassium-induced release of the above neurotransmitters and their metabolites in the striatum of awake and freely moving rats at ages 4, 8 and 12 months compared to wild-type (WT) rats. We found age-dependent abnormalities in basal DA, glutamate and acetylcholine in PINK1 KO rats and age-dependent abnormalities in basal DA metabolites in Parkin and LRRK2 KO rats. Parkin KO rats had increased glycine release while DJ-1 KO rats had decreased glutamate release and increased acetylcholine release compared to WT rats. All lines except DJ-1 KO rats showed age-dependent changes in release of one or more neurotransmitters. Our data suggest these rats may be useful for studies of PD-related synaptic dysfunction and neurotransmitter dynamics as well as studies of the normal and pathogenic functions of these genes with PD-linked mutations.