1,721,000 research outputs found
Brain-derived neurotrophic factor enhances GABA release probability and nonuniform distribution of N- and P/Q-type channels on release sites of hippocampal inhibitory synapses.
No full textLong-lasting exposures to brain-derived neurotrophic factor (BDNF) accelerate the functional maturation of GABAergic transmission in
embryonic hippocampal neurons, but the molecular bases of this phenomenon are still debated. Evidence in favor of a postsynaptic site
of action has been accumulated, but most of the data support a presynaptic site effect. A crucial issue is whether the enhancement of
evoked IPSCs (eIPSCs) induced by BDNF is attributable to an increase in any of the elementary parameters controlling neurosecretion,
namely the probability of release, the number of release sites, the readily releasable pool (RRP), and the quantal size.
Here, using peak-scaled variance analysis of miniature IPSCs, multiple probability fluctuation analysis, and cumulative amplitude
analysis of action potential-evoked postsynaptic currents, we show that BDNF increases release probability and vesicle replenishment
with little or no effect on the quantal size, the number of release sites, the RRP, and the Ca2 dependence of eIPSCs. BDNF treatment
changes markedly the distribution of Ca2 channels controlling neurotransmitter release. It enhances markedly the contribution of Nand
P/Q-type channels, which summed to100% (“supra-additivity”), and deletes the contribution of R-type channels. BDNF accelerates
the switch of presynaptic Ca2 channel distribution from “segregated” to “nonuniform” distribution. This maturation effect was
accompanied by an uncovered increased control of N-type channels on paired-pulse depression, otherwise dominated by P/Q-type
channels in untreated neurons. Nevertheless, BDNF preserved the fast recovery from depression associated with N-type channels. These
novel presynaptic BDNF actions derive mostly from an enhanced overlapping and better colocalization of N- and P/Q-type channels to
vesicle release sites.
Key words: neurotrophin
Direct autocrine inhibition and cAMP-dependent potentiation of single L-type Ca2+ channels in bovine chromaffin cells.
No full textAdvanced real-time recordings of neuronal activity with tailored patch pipettes, diamond multi-electrode arrays and electrochromic voltage-sensitive dyes
No full textTo understand the working principles of the nervous system is key to figure out its electrical activity and how this activity spreads along the neuronal network. It is therefore crucial to develop advanced techniques aimed to record in real time the electrical activity, from compartments of single neurons to populations of neurons, to understand how higher functions emerge from coordinated activity. To record from single neurons, a technique will be presented to fabricate patch pipettes able to seal on any membrane with a single glass type and whose shanks can be widened as desired. This dramatically reduces access resistance during whole-cell recording allowing fast intracellular and, if required, extracellular perfusion. To simultaneously record from many neurons, biocompatible probes will be described employing multi-electrodes made with novel technologies, based on diamond substrates. These probes also allow to synchronously record exocytosis and neuronal excitability and to stimulate neurons. Finally, to achieve even higher spatial resolution, it will be shown how voltage imaging, employing fast voltage-sensitive dyes and two-photon microscopy, is able to sample voltage oscillations in the brain spatially resolved and voltage changes in dendrites of single neurons at millisecond and micrometre resolution in awake animals
Il lavoratore come "persona" e la promessa della dignità
No full textIl saggio propone un'analisi comparatistica dell'approccio europeo e dell'approccio statunitense al tema della tutela della personalità del lavoratore subordinat
La dottrina sociale della Chiesa e la dignità del lavoratore nell'era globale
No full textIl contributo vuol essere una riflessione sull'influenza che la dottrina sociale della Chiesa può ancora esercitare al tempo della globalizzazione a difesa della dignità dei lavorator
FUNCTIONAL AND STRUCTURAL CONSTITUENTS OF NEURONAL Ca CHANNEL MODULATION BY NEUROTRANSMITTERS
No full textRileggendo The Employment Relationship di Bruno Veneziani
No full textnel lavoro si mettono a confronto e si discutono analiticamente due saggi di Veneziani, del 1986 e del 2009, mettendo in rilievo la continuità di ispirazione e l'evoluzione del pensiero dell'a., criticandone infine l'eccessiva fiducia nella categoria dei diritti fondamentali a garantire la missione protettiva del contratto di lavoro subordinat
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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