1,721,191 research outputs found
Effects of the neuronal phosphoprotein synapsin I on actin polymerization. I. Evidence for a phosphorylation-dependent nucleating effect
No full textKinetics of neuronal and endocrine secretion.
No full textCalcium (Ca2+) regulated secretion/exocytosis is a key mechanism for cell-cell communication. Neurotransmission and hormone release are the most studied and the best characterized of all secretion systems so far. Here, some dynamic aspects of secretory vesicle trafficking will be briefly reviewed with special emphasis on the differences between synaptic vesicle and dense-core vesicle turnover
Neurotensin in vitro markedly reduces the affinity in subcortical limbic 3-H N-prpyl-norapomorphine binding sites
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The synapsins: multitask modulators of neuronal development
No full textNeurons are examples of specialized cells that evolved the extraordinary ability to transmit electrochemical information in complex networks of interconnected cells. During their development, neurons undergo precisely regulated processes that define their lineage, positioning, morphogenesis and pattern of activity. The events leading to the establishment of functional neuronal networks follow a number of key steps, including asymmetric cell division from neuronal precursors, migration, establishment of polarity, neurite outgrowth and synaptogenesis. Synapsins are a family of abundant neuronal phosphoproteins that have been extensively studied for their role in the regulation of neurotransmission in presynaptic terminals. Beside their implication in the homeostasis of adult cells, synapsins influence the development of young neurons, interacting with cytoskeletal and vesicular components and regulating their dynamics. Although the exact molecular mechanisms determining synapsin function in neuronal development are still largely unknown, in this review we summarize the most important literature on the subject, providing a conceptual framework for the progress of present and future research
The role of synapsins in neuronal development.
No full textThe synapsins, the first identified synaptic vesicle-specific proteins, are phosphorylated on multiple sites by a number of protein kinases and are involved in neurite outgrowth and synapse formation as well as in synaptic transmission. In mammals, the synapsin family consists of at least 10 isoforms encoded by three distinct genes and composed by a mosaic of conserved and variable domains. The synapsins are highly conserved evolutionarily and orthologues have been found in invertebrates and lower vertebrates. Within nerve terminals, synapsins are implicated in multiple interactions with presynaptic proteins and the actin cytoskeleton. Via these interactions, synapsins control several mechanisms important for neuronal homeostasis. In this review, we describe the main functional features of the synapsins, in relation to the complex role played by these phosphoproteins in neuronal development
Chaoticity threshold in magnetized plasmas : numerical results in the weak coupling regime
Full text linkThe present paper is a numerical counterpart to the theoretical work [Carati et al., Chaos 22, 033124 (2012)]. We are concerned with the transition from order to chaos in a one-component plasma (a system of point electrons with mutual Coulomb interactions, in a uniform neutralizing background), the plasma being immersed in a uniform stationary magnetic field. In the paper [Carati et al., Chaos
22, 033124 (2012)], it was predicted that a transition should take place when the electron density is increased or the field decreased in such a way that the ratio between plasma and cyclotron frequencies becomes of order 1, irrespective of the value of the so-called Coulomb coupling parameter. Here, we perform numerical computations for a first principles model of N point
electrons in a periodic box, with mutual Coulomb interactions, using as a probe for chaoticity the time-autocorrelation function of magnetization. We consider two values of Coulomb coupling parameter (0.04 and 0.016) in the weak coupling regime, with N up to 512. A transition is found to occur for ratio between plasma and cyclotron frequencies in the range between 0.25 and 2, in fairly good agreement with the theoretical prediction. These results might be of interest for the problem of the breakdown of plasma confinement in fusion machines
Effects of the neuronal phosphoprotein synapsin I on actin polymerization. II. Analytical interpretation of kinetic curves
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