scholarly journals A centronuclear myopathy-causing mutation in dynamin-2 perturbs the actin-dependent structure of dendritic spines leading to excitatory synaptic defects in a murine model of the disease

2021 ◽  
Author(s):  
JORGE ARRIAGADA-DIAZ ◽  
Barbara Gomez ◽  
Lorena Prado-Vega ◽  
MICHELLE MATTAR-ARAOS ◽  
MARJORIE LABRANA-ALLENDE ◽  
...  
Keyword(s):  
Nervous System ◽  
Long Term Potentiation ◽  
Neuromuscular Disorder ◽  
Centronuclear Myopathy ◽  
Term Potentiation ◽  
The Central Nervous System ◽  
Central Synapses ◽  
Cytoskeleton Dynamics ◽  
Dynamin 2 ◽  
Cognitive Defects

Dynamin-2 is a large GTP-ase, member of the dynamin superfamily, that regulates membrane remodeling and cytoskeleton dynamics. In the mammalian nervous system dynamin-2 modulates synaptic vesicle (SV)-recycling at the nerve terminals and receptor-trafficking to and from postsynaptic densities (PSDs). Mutations in dynamin-2 cause autosomal dominant centronuclear myopathy (CNM), a congenital neuromuscular disorder characterized by progressive weakness and atrophy of distal skeletal muscles. Cognitive defects have also been reported in dynamin-2-linked CNM patients suggesting a concomitant impairment of the central nervous system. Here we addressed the mechanisms that lead to cognitive defects in dynamin-2-linked CNM using a knock-in mouse model that harbors the p.R465W mutation in dynamin-2, the most common causing CNM. Our results show that these mice exhibit reduced capability to learn and acquire spatial and recognition memory, impaired long-term potentiation of the excitatory synaptic strength and perturbed dendritic spine morphology, which seem to be associated with actin defects. Together, these data reveal for the first time that structural and functional synaptic defects underlie cognitive defects in the CNM context. In addition our results contribute to the still scarce knowledge about the importance of dynamin-2 at central synapses.

Developmental models of brain dysfunctions induced by targeted cellular ablations with methylazoxymethanol

1997 ◽  
Vol 77 (1) ◽  
pp. 199-215 ◽  
Author(s):  
F. Cattabeni ◽  
M. Di Luca
Keyword(s):  
Nervous System ◽  
Long Term Potentiation ◽  
Developmental Models ◽  
Neuronal Populations ◽  
Term Potentiation ◽  
Brain Malformations ◽  
Time Table ◽  
Dependent Protein ◽  
The Central Nervous System ◽  
Molecular Substrates

Abnormal brain development represents one of the major causes of neurological disorders in humans, and determining the factors responsible for generating specific brain malformations represents a formidable task for developmental neurobiology. The knowledge of the precise neurogenetic time table and the use of toxins, like methylazoxymethanol, able to interfere with neuroepithelial cells entering their last mitotic cycle, have allowed for targeted neuronal ablations in specific brain areas of the central nervous system (CNS) when administered at different gestational or postnatal days in various animal species. Of particular relevance are the studies in which ablations of neuronal populations of cortex, hippocampus, and cerebellum have been made. The results obtained show that these early ablations induce a number of neuroanatomic, neurochemical, and electrophysiological changes that give us the possibility to unravel the biochemical strategies utilized by surviving neurons to adapt to the perturbated environment. Most striking are the findings that target deprivation does not affect the survival of afferent neurons in the CNS (except for neurons of the lateral geniculate nucleus), in sharp contrast to the notion of target dependence for peripheral nervous system neurons. Animals showing selective ablations in the Ammon's horn of the hippocampus allow us to understand the complex biochemical pathways leading to changes in activity-dependent synaptic plasticity, and the data underscore the fundamental role of diverse Ca(2+)-dependent protein kinases, and their substrates, in modulating pre- and postsynaptic events during induction and maintenance of long-term potentiation (LTP). Because LTP represents a useful model to study molecular substrates of learning and memory, this animal model might be of relevance in understanding cognitive brain dysfunctions.

scholarly journals Multiplexed neurochemical transmission emulated using a dual-excitatory synaptic transistor

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Mingxue Ma ◽  
Yao Ni ◽  
Zirong Chi ◽  
Wanqing Meng ◽  
Haiyang Yu ◽  
...  
Keyword(s):  
Neural Network ◽  
Central Nervous System ◽  
Nervous System ◽  
Long Term Potentiation ◽  
Short Term ◽  
Term Potentiation ◽  
Binary Neural Network ◽  
Neuromorphic Systems ◽  
Human Brains

AbstractThe ability to emulate multiplexed neurochemical transmission is an important step toward mimicking complex brain activities. Glutamate and dopamine are neurotransmitters that regulate thinking and impulse signals independently or synergistically. However, emulation of such simultaneous neurotransmission is still challenging. Here we report design and fabrication of synaptic transistor that emulates multiplexed neurochemical transmission of glutamate and dopamine. The device can perform glutamate-induced long-term potentiation, dopamine-induced short-term potentiation, or co-release-induced depression under particular stimulus patterns. More importantly, a balanced ternary system that uses our ambipolar synaptic device backtrack input ‘true’, ‘false’ and ‘unknown’ logic signals; this process is more similar to the information processing in human brains than a traditional binary neural network. This work provides new insight for neuromorphic systems to establish new principles to reproduce the complexity of a mammalian central nervous system from simple basic units.

Neurotrophins and Proneurotrophins: Focus on Synaptic Activity and Plasticity in the Brain

2017 ◽  
Vol 23 (6) ◽  
pp. 587-604 ◽  
Author(s):  
Julien Gibon ◽  
Philip A. Barker
Keyword(s):  
Long Term Potentiation ◽  
Synaptic Activity ◽  
Cellular Processes ◽  
Term Potentiation ◽  
Neurotrophin 3 ◽  
New Findings ◽  
The Central Nervous System ◽  
The Brain

Neurotrophins have been intensively studied and have multiple roles in the brain. Neurotrophins are first synthetized as proneurotrophins and then cleaved intracellularly and extracellularly. Increasing evidences demonstrate that proneurotrophins and mature neurotrophins exerts opposing role in the central nervous system. In the present review, we explore the role of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin 3 (NT3), and neurotrophin 4 (NT4) and their respective proform in cellular processes related to learning and memory. We focused on their roles in synaptic activity and plasticity in the brain with an emphasis on long-term potentiation, long-term depression, and basal synaptic transmission in the hippocampus and the temporal lobe area. We also discuss new findings on the role of the Val66Met polymorphism on the BDNF propeptide on synaptic activity.

scholarly journals Effect of Barbiturates on Synaptic Currents

1976 ◽  
Vol 4 (3) ◽  
pp. 199-202 ◽  
Author(s):  
T. A. Torda ◽  
P. W. Gage
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Neuromuscular Junction ◽  
Synaptic Transmission ◽  
Time Constant ◽  
Mode Of Action ◽  
Synaptic Currents ◽  
End Plate ◽  
The Central Nervous System ◽  
Central Synapses

Thiopentone and pentobarbitone reduce the time constant of decay of miniature end-plate currents when applied in anaesthetic concentrations to the neuromuscular junction. Such an effect at central synapses would lead to failure of synaptic transmission in the central nervous system and may reflect a common mode of action of many anaesthetic drugs.

scholarly journals Cyclase-associated protein 2 dimerization regulates cofilin in synaptic plasticity and Alzheimer's disease

2020 ◽  
Vol 2 (2) ◽  
Author(s):  
Silvia Pelucchi ◽  
Lina Vandermeulen ◽  
Lara Pizzamiglio ◽  
Bahar Aksan ◽  
Jing Yan ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Actin Cytoskeleton ◽  
Structural Plasticity ◽  
Long Term Potentiation ◽  
Brain Diseases ◽  
Biological Trait ◽  
Term Potentiation ◽  
Cytoskeleton Dynamics

Abstract Regulation of actin cytoskeleton dynamics in dendritic spines is crucial for learning and memory formation. Hence, defects in the actin cytoskeleton pathways are a biological trait of several brain diseases, including Alzheimer's disease. Here, we describe a novel synaptic mechanism governed by the cyclase-associated protein 2, which is required for structural plasticity phenomena and completely disrupted in Alzheimer's disease. We report that the formation of cyclase-associated protein 2 dimers through its Cys32 is important for cyclase-associated protein 2 binding to cofilin and for actin turnover. The Cys32-dependent cyclase-associated protein 2 homodimerization and association to cofilin are triggered by long-term potentiation and are required for long-term potentiation-induced cofilin translocation into spines, spine remodelling and the potentiation of synaptic transmission. This mechanism is specifically affected in the hippocampus, but not in the superior frontal gyrus, of both Alzheimer's disease patients and APP/PS1 mice, where cyclase-associated protein 2 is down-regulated and cyclase-associated protein 2 dimer synaptic levels are reduced. Notably, cyclase-associated protein 2 levels in the cerebrospinal fluid are significantly increased in Alzheimer's disease patients but not in subjects affected by frontotemporal dementia. In Alzheimer's disease hippocampi, cofilin association to cyclase-associated protein 2 dimer/monomer is altered and cofilin is aberrantly localized in spines. Taken together, these results provide novel insights into structural plasticity mechanisms that are defective in Alzheimer's disease.

scholarly journals Modeling Resilience to Damage in Multiple Sclerosis: Plasticity Meets Connectivity

2019 ◽  
Vol 21 (1) ◽  
pp. 143 ◽  
Author(s):  
Mario Stampanoni Bassi ◽  
Ennio Iezzi ◽  
Luigi Pavone ◽  
Georgia Mandolesi ◽  
Alessandra Musella ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Synaptic Plasticity ◽  
Network Architecture ◽  
White Matter Lesions ◽  
Long Term Potentiation ◽  
Chronic Inflammatory Disease ◽  
Brain Network ◽  
Term Potentiation ◽  
The Central Nervous System ◽  
Efficient Information

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS) characterized by demyelinating white matter lesions and neurodegeneration, with a variable clinical course. Brain network architecture provides efficient information processing and resilience to damage. The peculiar organization characterized by a low number of highly connected nodes (hubs) confers high resistance to random damage. Anti-homeostatic synaptic plasticity, in particular long-term potentiation (LTP), represents one of the main physiological mechanisms underlying clinical recovery after brain damage. Different types of synaptic plasticity, including both anti-homeostatic and homeostatic mechanisms (synaptic scaling), contribute to shape brain networks. In MS, altered synaptic functioning induced by inflammatory mediators may represent a further cause of brain network collapse in addition to demyelination and grey matter atrophy. We propose that impaired LTP expression and pathologically enhanced upscaling may contribute to disrupting brain network topology in MS, weakening resilience to damage and negatively influencing the disease course.

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