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Abstract Treatment with L-3,4-dihydroxyphenylalanine (L-Dopa) compensates for decreased striatal dopamine (DA) levels and reduces Parkinson’s disease (PD) symptoms. However, during disease progression, L-Dopa-induced dyskinesia (LID) develops virtually in all PD patients, making the control of PD symptoms difficult. Thus, understanding the mechanisms underlying LID and the control of these motor abnormalities is a major issue in the care of PD patients. From experimental and clinical studies, a complex cascade of molecular and cellular events emerges, but the primary determinants of LID are still unclear. Here, with a translational approach, including four animal models and a wide cohort of PD patients, we show that striatal DA denervation is the major causal factor for the emergence of LID, while α-synuclein aggregates do not seem to play a significant role. Our data also support the concept that maladaptive basal ganglia plasticity is the main pathophysiological mechanism underlying LID.

Abstract Increasing efforts have been made to elucidate how genetic and environmental factors interact in Parkinson’s disease (PD). In the present study, we assessed the development of symptoms on a genetic PD rat model that overexpresses human α-synuclein (Snca +/+) at a presymptomatic age, exposed to a pro-inflammatory insult by intraperitoneal injection of lipopolysaccharide (LPS), using immunohistology, high-dimensional flow cytometry, constant potential amperometry, and behavioral analyses. A single injection of LPS into WT and Snca +/+ rats triggered long-lasting increase in the activation of pro-inflammatory microglial markers, monocytes, and T lymphocytes. However, only LPS Snca +/+ rats showed dopaminergic neuronal loss in the substantia nigra pars compacta (SNpc), associated with a reduction in the release of evoked dopamine in the striatum. No significant changes were observed in the behavioral domain. We propose our double-hit animal as a reliable model to investigate the mechanisms whereby α-synuclein and inflammation interact to promote neurodegeneration in PD.

The vascular endothelial growth factors (VEGFs) and their cognate receptors (VEGFRs), besides their well-known involvement in physiological angiogenesis/lymphangiogenesis and in diseases associated to pathological vessel formation, play multifaceted functions in the central nervous system (CNS). In addition to shaping brain development, by controlling cerebral vasculogenesis and regulating neurogenesis as well as astrocyte differentiation, the VEGFs/VEGFRs axis exerts essential functions in the adult brain both in physiological and pathological contexts. In this article, after describing the physiological VEGFs/VEGFRs functions in the CNS, we focus on the VEGFs/VEGFRs involvement in neurodegenerative diseases by reviewing the current literature on the rather complex VEGFs/VEGFRs contribution to the pathogenic mechanisms of Alzheimer’s (AD) and Parkinson’s (PD) diseases. Thereafter, based on the outcome of VEGFs/VEGFRs targeting in animal models of AD and PD, we discuss the factual relevance of pharmacological VEGFs/VEGFRs modulation as a novel and potential disease-modifying approach for these neurodegenerative pathologies. Specific VEGFRs targeting, aimed at selective VEGFR-1 inhibition, while preserving VEGFR-2 signal transduction, appears as a promising strategy to hit the molecular mechanisms underlying AD pathology. Moreover, therapeutic VEGFs-based approaches can be proposed for PD treatment, with the aim of fine-tuning their brain levels to amplify neurotrophic/neuroprotective effects while limiting an excessive impact on vascular permeability.

Cajal-Retzius neurons number drastically decreases during postnatal life. Here, authors show that their programmed death is required for the construction of functional hippocampal circuits and memory with aberrant survival leading to gamma rhythmopathies and susceptibility to seizures.

Group I metabotropic glutamate receptors (mGluRI), including mGluR1 and mGluR5 subtypes, modulate essential brain functions by affecting neuronal excitability, intracellular calcium dynamics, protein synthesis, dendritic spine formation, and synaptic transmission and plasticity. Nowadays, it is well appreciated that the mGluRI-dependent long-term depression (LTD) of glutamatergic synaptic transmission (mGluRI-LTD) is a key mechanism by which mGluRI shapes connectivity in various cerebral circuitries, directing complex brain functions and behaviors, and that it is deranged in several neurological and psychiatric illnesses, including neurodevelopmental disorders, neurodegenerative diseases, and psychopathologies. Here, we will provide an updated overview of the physiopathology of mGluRI-LTD, by describing mechanisms of induction and regulation by endogenous mGluRI interactors, as well as functional physiological implications and pathological deviations.

Introduction Emergency medicine resident physicians are required to complete observational ride-alongs with emergency medical services (EMS) units as part of their curriculum as per the ACGME. We created this curriculum to expose emergency medicine residents to the equipment they will encounter in the prehospital setting, discuss basic EMS operations and the challenges of working in the prehospital environment, and review the limitations that restrict care provided by EMS professionals. Methods We created a series of five simulation cases for resident physicians participating in an EMS ride-along rotation. Each case was implemented with three to four residents at a time. A critical action checklist was used to assess participants during the scenarios. Following each simulation, a debriefing was conducted to discuss EMS operations and the impact on providers. At the conclusion of the session, participants completed a course evaluation survey. Results Thirteen emergency medicine resident physicians took part in this curriculum from October 2020 through January 2021. Results indicated that the participants gained insight into the prehospital environment, felt more prepared to complete their ride-alongs, and were engaged and satisfied with the introduction to EMS program. Discussion Simulation allowed emergency medicine residents to be exposed to the complex nature of prehospital care and prepared them for their ride-along sessions. The five cases provided significant breadth and depth of potential prehospital care issues, and the residents were able to discuss the medical, policy, and operational challenges presented as part of each case.

Exposure to aversive events during sensitive developmental periods can affect the preferential coping strategy adopted by individuals later in life, leading to either stress-related psychiatric disorders, including depression, or to well-adaptation to future adversity and sources of stress, a behavior phenotype termed “resilience”.We have previously shown that interfering with the development of mother-pups bond with the Repeated Cross Fostering (RCF) stress protocol can induce resilience to depression-like phenotype in adult C57BL/6J female mice. Here, we used patch-clamp recording in midbrain slice combined with both in vivo and ex vivo pharmacology to test our hypothesis of a link between electrophysiological modifications of dopaminergic neurons in the intermediate Ventral Tegmental Area (VTA) of RCF animals and behavioral resilience. We found reduced hyperpolarization-activated (Ih) cation current amplitude and evoked firing in VTA dopaminergic neurons from both young and adult RCF female mice. In vivo, VTA-specific pharmacological manipulation of the Ih current reverted the pro-resilient phenotype in adult early-stressed mice or mimicked behavioral resilience in adult control animals.This is the first evidence showing how pro-resilience behavior induced by early events is linked to a long-lasting reduction of Ih current and excitability in VTA dopaminergic neurons.