Search results for "Dendrite"
showing 10 items of 60 documents
Sequential acquisition of cacophony calcium currents, sodium channels and voltage-dependent potassium currents affects spike shape and dendrite growt…
2014
During metamorphosis the CNS undergoes profound changes to accommodate the switch from larval to adult behaviors. In Drosophila and other holometabolous insects, adult neurons differentiate either from respecified larval neurons, newly born neurons, or are born embryonically but remain developmentally arrested until differentiation during pupal life. This study addresses the latter in the identified Drosophila flight motoneuron 5. In situ patch-clamp recordings, intracellular dye fills and immunocytochemistry address the interplay between dendritic shape, excitability and ionic current development. During pupal life, changes in excitability and spike shape correspond to a stereotyped, progr…
The GRIP1/14-3-3 Pathway Coordinates Cargo Trafficking and Dendrite Development
2014
SummaryRegulation of cargo transport via adaptor molecules is essential for neuronal development. However, the role of PDZ scaffolding proteins as adaptors in neuronal cargo trafficking is still poorly understood. Here, we show by genetic deletion in mice that the multi-PDZ domain scaffolding protein glutamate receptor interacting protein 1 (GRIP1) is required for dendrite development. We identify an interaction between GRIP1 and 14-3-3 proteins that is essential for the function of GRIP1 as an adaptor protein in dendritic cargo transport. Mechanistically, 14-3-3 binds to the kinesin-1 binding region in GRIP1 in a phospho-dependent manner and detaches GRIP1 from the kinesin-1 motor protein …
Energy efficient modulation of dendritic processing functions
1998
The voltage dependent ionic conductances and the passive properties of the neural membrane determine how external inputs are processed by the dendritic tree, and define the computational characteristics of neurons. However, what controls these characteristics and how they are implemented at the single neuron level, in such a way that an external input results in the coding of the appropriate output, is essentially unknown. We show here that a slow inactivation of the Na+ channel, involved in the attenuation and/or failure of APs in the dendrites, acts as an active and energy efficient filter of synaptic input, and results in an activity-dependent control of the properties of individual neur…
Extraction of objects from structured backgrounds in the cat superior colliculus. Part II
1980
Specific changes occur in the cells of the uppers layers of the cat's superior colliculus when a two dimensional noise (background) is superimposed onto a deterministic signal (spot of light). Some of the measurements can be interpreted as meaning that some cells only react to certain relative movements of object (spot) and background (noise). The movement of the visual background is interpreted as environmental movement occurring due to the animal's own movement. The results of the measurements provide all the necessary presuppositions for a distinction between the animal's own velocity and that of the object (Part I). The experimental results can be interpreted with a model. The essential…
Truncated TrkB receptor-induced outgrowth of dendritic filopodia involves the p75 neurotrophin receptor.
2004
The Trk family of receptor tyrosine kinases and the p75 receptor (p75NTR) mediate the effects of neurotrophins on neuronal survival, differentiation and synaptic plasticity. The neurotrophin BDNF and its cognate receptor tyrosine kinase, TrkB.FL, are highly expressed in neurons of the central nervous system. At later stages in postnatal development the truncated TrkB splice variants (TrkB.T1, TrkB.T2) become abundant. However, the signalling and function of these truncated receptors remained largely elusive.We show that overexpression of TrkB.T1 in hippocampal neurons induces the formation of dendritic filopodia, which are known precursors of synaptic spines. The induction of filopodia by T…
Electrophysiological and morphological properties of Cajal–Retzius cells with different ontogenetic origins
2010
International audience; The different origins of Cajal-Retzius cells (CRc) as well as their diverse molecular profile suggest that this cell type may represent different neuronal subpopulations. In order to investigate whether CRc from different origins show distinct functional or morphological characteristics we used transgenic Dbx1(cre);ROSA26(YFP) mice in which two subpopulations of CRc, originating from the septum and ventral pallium (VP) at the pallial-subpallial border (PSB), were permanently labeled by yellow fluorescent protein (YFP) expression. Electrophysiological properties of YFP(+) and YFP(-) CRc were investigated by whole-cell patch-clamp recordings, while a thorough somatoden…
Clustering transmembrane-agrin induces filopodia-like processes on axons and dendrites
2005
The transmembrane form of agrin (TM-agrin) is primarily expressed in the CNS, particularly on neurites. To analyze its function, we clustered TM-agrin on neurons using anti-agrin antibodies. On axons from the chick CNS and PNS as well as on axons and dendrites from mouse hippocampal neurons anti-agrin antibodies induced the dose- and time-dependent formation of numerous filopodia-like processes. The processes appeared within minutes after antibody addition and contained a complex cytoskeleton. Formation of processes required calcium, could be inhibited by cytochalasine D, but was not influenced by staurosporine, heparin or pervanadate. Time-lapse video microscopy revealed that the processes…
Huntingtin mediates dendritic transport of β-actin mRNA in rat neurons
2011
Transport of mRNAs to diverse neuronal locations via RNA granules serves an important function in regulating protein synthesis within restricted sub-cellular domains. We recently detected the Huntington's disease protein huntingtin (Htt) in dendritic RNA granules; however, the functional significance of this localization is not known. Here we report that Htt and the huntingtin-associated protein 1 (HAP1) are co-localized with the microtubule motor proteins, the KIF5A kinesin and dynein, during dendritic transport of β-actin mRNA. Live cell imaging demonstrated that β-actin mRNA is associated with Htt, HAP1, and dynein intermediate chain in cultured neurons. Reduction in the levels of Htt, H…
Ray optics behavior of flux avalanche propagation in superconducting films
2015
Experimental evidence of wave properties of dendritic flux avalanches in superconducting films is reported. Using magneto-optical imaging the propagation of dendrites across boundaries between a bare NbN film and areas coated by a Cu layer was visualized, and it was found that the propagation is refracted in full quantitative agreement with Snell's law. For the studied film of 170 nm thickness and a $0.9\phantom{\rule{0.28em}{0ex}}\ensuremath{\mu}\mathrm{m}$ thick metal layer, the refractive index was close to $n=1.4$. The origin of the refraction is believed to be caused by the dendrites propagating as an electromagnetic shock wave, similar to damped modes considered previously for normal …
Ray optics behavior of flux avalanche propagation in superconducting films
2015
Experimental evidence of wave properties of dendritic flux avalanches in superconducting films is reported. Using magneto-optical imaging the propagation of dendrites across boundaries between a bare NbN film and areas coated by a Cu layer was visualized, and it was found that the propagation is refracted in full quantitative agreement with Snell’s law. For the studied film of 170 nm thickness and a 0.9 μm thick metal layer, the refractive index was close to n = 1.4. The origin of the refraction is believed to be caused by the dendrites propagating as an electromagnetic shock wave, similar to damped modes considered previously for normal metals. The analogy is justified by the large dissipa…