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chemical synapse

Sarbendu Rakshit, Bidesh K Bera, Dibakar Ghosh, Sudeshna Sinha
We study synchronization of dynamical systems coupled in time-varying network architectures, composed of two or more network topologies, corresponding to different interaction schemes. As a representative example of this class of time-varying hypernetworks, we consider coupled Hindmarsh-Rose neurons, involving two distinct types of networks, mimicking interactions that occur through the electrical gap junctions and the chemical synapses. Specifically, we consider the connections corresponding to the electrical gap junctions to form a small-world network, while the chemical synaptic interactions form a unidirectional random network...
May 2018: Physical Review. E
Sahika Inal, Jonathan Rivnay, Andreea-Otilia Suiu, George G Malliaras, Iain McCulloch
The emerging field of organic bioelectronics bridges the electronic world of organic-semiconductor-based devices with the soft, predominantly ionic world of biology. This crosstalk can occur in both directions. For example, a biochemical reaction may change the doping state of an organic material, generating an electronic readout. Conversely, an electronic signal from a device may stimulate a biological event. Cutting-edge research in this field results in the development of a broad variety of meaningful applications, from biosensors and drug delivery systems to health monitoring devices and brain-machine interfaces...
June 6, 2018: Accounts of Chemical Research
Maura Ferrer-Ferrer, Alexander Dityatev
Accumulating data support the importance of interactions between pre- and postsynaptic neuronal elements with astroglial processes and extracellular matrix (ECM) for formation and plasticity of chemical synapses, and thus validate the concept of a tetrapartite synapse. Here we outline the major mechanisms driving: (i) synaptogenesis by secreted extracellular scaffolding molecules, like thrombospondins (TSPs), neuronal pentraxins (NPs) and cerebellins, which respectively promote presynaptic, postsynaptic differentiation or both; (ii) maturation of synapses via reelin and integrin ligands-mediated signaling; and (iii) regulation of synaptic plasticity by ECM-dependent control of induction and consolidation of new synaptic configurations...
2018: Frontiers in Neuroanatomy
Hanna Juhola, Pekka A Postila, Sami Rissanen, Fabio Lolicato, Ilpo Vattulainen, Tomasz Róg
Lipophilic neurotransmitters (NTs) such as dopamine are chemical messengers enabling neurotransmission by adhering onto the extracellular surface of a post-synaptic membrane in a synapse, followed by binding to their receptors. Previous studies have shown that the strength of the NT-membrane association is dependent on the lipid composition of the membrane. Negatively charged lipids such as phosphatidylserine, phosphatidylglycerol, and phosphatidic acid have been indicated to promote NT-membrane binding, however these anionic lipids reside almost exclusively in the intracellular leaflet of the post-synaptic membrane instead of the extracellular leaflet facing the synaptic cleft...
May 31, 2018: Neuroscience
Elham Bayat Mokhtari, J Josh Lawrence, Emily F Stone
Neurons in a micro-circuit connected by chemical synapses can have their connectivity affected by the prior activity of the cells. The number of synapses available for releasing neurotransmitter can be decreased by repetitive activation through depletion of readily releasable neurotransmitter (NT), or increased through facilitation, where the probability of release of NT is increased by prior activation. These competing effects can create a complicated and subtle range of time-dependent connectivity. Here we investigate the probabilistic properties of facilitation and depression (FD) for a presynaptic neuron that is receiving a Poisson spike train of input...
May 29, 2018: Journal of Mathematical Neuroscience
M Mielczarek, M Frąszczak, E Nicolazzi, J L Williams, J Szyda
BACKGROUND: The number of studies of Copy Number Variation in cattle has increased in recent years. This has been prompted by the increased availability of data on polymorphisms and their relationship with phenotypes. In addition, livestock species are good models for some human phenotypes. In the present study, we described the landscape of CNV driven genetic variation in a large population of 146 individuals representing 13 cattle breeds, using whole genome DNA sequence. RESULTS: A highly significant variation among all individuals and within each breed was observed in the number of duplications (P < 10-15 ) and in the number of deletions (P < 10-15 )...
May 29, 2018: BMC Genomics
Riley Perszyk, Brooke M Katzman, Hirofumi Kusumoto, Steven A Kell, Matthew P Epplin, Yesim A Tahirovic, Rhonda L Moore, David Menaldino, Pieter Burger, Dennis C Liotta, Stephen F Traynelis
N-methyl-d-aspartate receptors (NMDARs) are an important receptor in the brain and have been implicated in multiple neurological disorders. Many non-selective NMDAR-targeting drugs are poorly tolerated, leading to efforts to target NMDAR subtypes to improve the therapeutic index. We describe here a series of negative allosteric NMDAR modulators with submaximal inhibition at saturating concentrations. Modest changes to the chemical structure interconvert negative and positive modulation. All modulators share the ability to enhance agonist potency and are use-dependent, requiring the binding of both agonists before modulators act with high potency...
May 24, 2018: ELife
Anna C Schneider, Henriette A Seichter, Susanne Neupert, A Maren Hochhaus, Carmen R Smarandache-Wellmann
Locomotor systems are widely used to study rhythmically active neural networks. These networks have to be coordinated in order to produce meaningful behavior. The crayfish swimmeret system is well suited to investigate such coordination of distributed neural oscillators because the neurons and their connectivity for generating and especially for coordinating the motor output are identified. The system maintains a fixed phase lag between the segmental oscillators, independent of cycle period. To further the understanding of the system's plasticity for keeping the phase lag fixed, we profiled the neurotransmitters used by the Coordinating Neurons, which are necessary and sufficient for coordination of the segmental oscillators...
2018: PloS One
In-Sook Jeon, Hye-Ryun Kim, Eun-Young Shin, Eung-Gook Kim, Heon-Seok Han, Jin-Tae Hong, Hak-Kyo Lee, Ki-Duk Song, Joong-Kook Choi
Calcium mobilization is necessary for cell movement during embryonic development, lymphocyte synapse formation, wound healing, and cancer cell metastasis. Depletion of calcium in the lumen of the endoplasmic reticulum using inositol triphosphate (IP3) or thapsigargin (TG) is known to induce oligomerization and cytoskeleton-mediated translocation of stromal interaction molecule 1 (STIM1) to the plasma membrane, where it interacts with the calcium release-activated calcium channel Orai1 to mediate calcium influx; this process is referred to as store-operated calcium entry (SOCE)...
May 21, 2018: Experimental & Molecular Medicine
Roman A Romanov, Robert S Lasher, Brigit High, Logan E Savidge, Adam Lawson, Olga A Rogachevskaja, Haitian Zhao, Vadim V Rogachevsky, Marina F Bystrova, Gleb D Churbanov, Igor Adameyko, Tibor Harkany, Ruibiao Yang, Grahame J Kidd, Philippe Marambaud, John C Kinnamon, Stanislav S Kolesnikov, Thomas E Finger
Conventional chemical synapses in the nervous system involve a presynaptic accumulation of neurotransmitter-containing vesicles, which fuse with the plasma membrane to release neurotransmitters that activate postsynaptic receptors. In taste buds, type II receptor cells do not have conventional synaptic features but nonetheless show regulated release of their afferent neurotransmitter, ATP, through a large-pore, voltage-gated channel, CALHM1. Immunohistochemistry revealed that CALHM1 was localized to points of contact between the receptor cells and sensory nerve fibers...
May 8, 2018: Science Signaling
Wen Zhang, Shi-Huan Tang, Yi Zhang, De-Feng Li, Hong-Jun Yang, Yi Zhang, Fei-Fei Guo
The traditional Chinese medicine prescription Yueju Wan has the function of regulating qi-flowing for activating stagnancy and resolving food stagnation, which is now used for the treatment of depression and gastrointestinal related diseases. In this study, an integrative pharmacological method was adopted to predict the targets and pathways of Yueju Wan and explore its molecular mechanism for depression and gastrointestinal dysfunction with the same treatment. First, disease targets were collected from Human Phenotype Ontology database, 201 targets related to depression and 474 targets related to gastrointestinal dysfunction, including 95 common targets of these two...
April 2018: Zhongguo Zhong Yao za Zhi, Zhongguo Zhongyao Zazhi, China Journal of Chinese Materia Medica
Shira Sardi, Roni Vardi, Amir Goldental, Yael Tugendhaft, Herut Uzan, Ido Kanter
Experimental and theoretical results reveal a new underlying mechanism for fast brain learning process, dendritic learning, as opposed to the misdirected research in neuroscience over decades, which is based solely on slow synaptic plasticity. The presented paradigm indicates that learning occurs in closer proximity to the neuron, the computational unit, dendritic strengths are self-oscillating, and weak synapses, which comprise the majority of our brain and previously were assumed to be insignificant, play a key role in plasticity...
May 4, 2018: ACS Chemical Neuroscience
Rohit Abraham John, Fucai Liu, Nguyen Anh Chien, Mohit R Kulkarni, Chao Zhu, Qundong Fu, Arindam Basu, Zheng Liu, Nripan Mathews
Emulation of brain-like signal processing with thin-film devices can lay the foundation for building artificially intelligent learning circuitry in future. Encompassing higher functionalities into single artificial neural elements will allow the development of robust neuromorphic circuitry emulating biological adaptation mechanisms with drastically lesser neural elements, mitigating strict process challenges and high circuit density requirements necessary to match the computational complexity of the human brain...
May 4, 2018: Advanced Materials
Girisaran Gangatharan, Sylvie Schneider-Maunoury, Marie Anne Breau
Neuronal circuits, the functional building blocks of the nervous system, assemble during development through a series of dynamic processes including the migration of neurons to their final position, the growth and navigation of axons and their synaptic connection with target cells. While the role of chemical cues in guiding neuronal migration and axonal development has been extensively analysed, the contribution of mechanical inputs, such as forces and stiffness, has received far less attention. In this article, we review the in vitro and more recent in vivo studies supporting the notion that mechanical signals are critical for multiple aspects of neuronal circuit assembly, from the emergence of axons to the formation of functional synapses...
June 2018: Biology of the Cell
Ronald S Petralia, Ya-Xian Wang, Mark P Mattson, Pamela J Yao
Invaginating structures at chemical synapses in the mammalian nervous system exist in presynaptic axon terminals, postsynaptic spines or dendrites, and glial processes. These invaginating structures can be divided into three categories. The first category includes slender protrusions invaginating into axonal terminals, postsynaptic spines, or glial processes. Best known examples of this category are spinules extending from postsynaptic spines into presynaptic terminals in forebrain synapses. Another example of this category are protrusions from inhibitory presynaptic terminals invaginating into postsynaptic neuronal somas...
2018: Frontiers in Synaptic Neuroscience
Ji-Jie Pang, Zhuo Yang, Roy A Jacoby, Samuel M Wu
Some mammalian rod bipolar cells (RBCs) can receive excitatory chemical synaptic inputs from both rods and cones (DBCR2 ), but anatomical evidence for mammalian cone-RBC contacts has been sparse. We examined anatomical cone-RBC contacts using neurobiotin (NB) to visualize individual mouse cones and standard immuno-markers to identify RBCs, cone pedicles and synapses in mouse and baboon retinas. Peanut agglutinin (PNA) stained the basal membrane of all cone pedicles, and mouse cones were positive for red/green (R/G)-opsin, whereas baboon cones were positive for calbindin D-28k...
April 18, 2018: Journal of Comparative Neurology
Bronac Flanagan, Liam McDaid, John Wade, KongFatt Wong-Lin, Jim Harkin
The ability of astrocytes to rapidly clear synaptic glutamate and purposefully release the excitatory transmitter is critical in the functioning of synapses and neuronal circuits. Dysfunctions of these homeostatic functions have been implicated in the pathology of brain disorders such as mesial temporal lobe epilepsy. However, the reasons for these dysfunctions are not clear from experimental data and computational models have been developed to provide further understanding of the implications of glutamate clearance from the extracellular space, as a result of EAAT2 downregulation: although they only partially account for the glutamate clearance process...
April 2018: PLoS Computational Biology
Ranhua Xiong, Peter Verstraelen, Jo Demeester, Andre G Skirtach, Jean-Pierre Timmermans, Stefaan C De Smedt, Winnok H De Vos, Kevin Braeckmans
Neurodevelopmental and neurodegenerative disorders are characterized by subtle alterations in synaptic connections and perturbed neuronal network functionality. A hallmark of neuronal connectivity is the presence of dendritic spines, micron-sized protrusions of the dendritic shaft that compartmentalize single synapses to fine-tune synaptic strength. However, accurate quantification of spine density and morphology in mature neuronal networks is hampered by the lack of targeted labeling strategies. To resolve this, we have optimized a method to deliver cell-impermeable compounds into selected cells based on Spatially resolved NAnoparticle-enhanced Photoporation (SNAP)...
2018: Frontiers in Cellular Neuroscience
Hayder Amin, Michele Dipalo, Francesco De Angelis, Luca Berdondini
A controlled geometry of in vitro neuronal networks allows investigation of the cellular mechanisms that underlie neuron-to-neuron and neuron-extracellular matrix interactions, which are essential to biomedical research. Herein, we report a selective guidance of primary hippocampal neurons by using arrays of three-dimensional vertical nanopillars (NPs) functionalized with a specific adhesion-promoting molecule-poly-dl-ornithine (PDLO). We show that 90% of neuronal cells are guided exclusively on the combinatorial PDLO/NP substrate...
May 2, 2018: ACS Applied Materials & Interfaces
G Aleph Prieto, Liqi Tong, Erica D Smith, Carl W Cotman
CNS inflammatory responses are linked to cognitive impairment in humans. Research in animal models supports this connection by showing that inflammatory cytokines suppress long-term potentiation (LTP), the best-known cellular correlate of memory. Cytokine-induced modulation of LTP has been previously studied in vivo or in brain slices, two experimental approaches containing multiple cell populations responsive to cytokines. In their target cells, cytokines commonly increase the expression of multiple cytokines, thus increasing the complexity of brain cytokine networks even after single-cytokine challenges...
April 4, 2018: Neurochemical Research
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