Where results make sense

About us   |   Why use us?   |   Reviews   |   PR   |   Contact us

Topic: Presynaptic terminal

    Note: these results are not from the primary (high quality) database.

Ads by Google

In the News (Thu 24 Dec 09)

Northern Trust

Marvin Harrison

Peter Chernin

Gary Locke

Match Play

Penelope Cruz

Mickey Rourke

AR Rahman

Danny Boyle

Hugh Jackman

Search Results for presynaptic - Encyclopædia Britannica Two factors are essential for the release of the neurotransmitter from the presynaptic terminal: (1) depolarization of the terminal and (2) the presence of calcium ions (Ca2+) in the extracellular... After neurotransmitter is released from the presynaptic terminal, it diffuses across the synaptic cleft and binds to receptor proteins on the postsynaptic membrane. Expand your search on presynaptic with these databases: www.britannica.com /search?query=presynaptic&submit=Find&source=MWTEXT   (299 words)

Stanford Encyclopedia article At electrical synapses, the current generated by the action potential at the presynaptic neuron flows directly into the postsynaptic cell, which is physically connected to the presynaptic terminal by a so-called gap junction. As presented in Section 3.2, the information flow between neurons in chemical synapses is initiated by the release of transmitters in the presynaptic terminal. However, ways in which these quantum processes might be relevant for mental activity, and in which their interactions with mental states are conceived, have hardly been elaborated so far. www.quantumconsciousness.org /StanfordEncyclopediaarticle.htm   (8846 words)

Novel Mechanism for Presynaptic Inhibition: GABAA Receptors Affect the Release Machinery -- Parnas et al. 84 (3): 1240 -- Journal of Neurophysiology Dudel J. Presynaptic inhibition of the excitatory nerve terminal in the neuromuscular junction of the crayfish. Dudel J. The mechanism of presynaptic inhibition at the crayfish neuromuscular junction. Slutsky I, Parnas H, and Parnas I. Presynaptic effects of muscarine on ACh release at the frog neuromuscular junction. jn.physiology.org /cgi/content/full/84/3/1240   (4118 words)

Proteins involved in synaptic vesicle trafficking -- Augustine et al. 520 (1): 33 -- The Journal of Physiology Online Synaptic vesicles within the interior of the presynaptic terminal are too far away from the plasma membrane to participate immediately in neurotransmitter release during an action potential. By analogy, perturbation of a presynaptic protein should block the reaction in which this protein participates, causing a loss of downstream trafficking intermediates and a parallel accumulation of upstream reactants. We will use this model to summarize how microinjected reagents change presynaptic structure and function and how such results yield our current view of the molecular basis of synaptic vesicle trafficking. jp.physoc.org /cgi/content/full/520/1/33   (6317 words)

Study of the Inhibitor of the Crayfish Neuromuscular Junction by Presynaptic Voltage Control -- Vyshedskiy and Lin 77 (1): 103 -- Journal of Neurophysiology Placement of presynaptic voltage electrodes in the primary branch (1st column) invariably failed to control potentials in terminal branches regardless of the positions of the muscle fibers we studied. of the presynaptic branch of the crayfish inhibitor. Presynaptic voltage control offers a large degree of freedom in the waveform of the presynaptic pulse. jn.physiology.org /cgi/content/full/77/1/103   (7118 words)

Distinct Roles of Kv1 and Kv3 Potassium Channels at the Calyx of Held Presynaptic Terminal -- Ishikawa et al. 23 (32): 10445 -- Journal of Neuroscience Presynaptic action potentials were evoked by a depolarizing pulse of 1 msec in duration. Presynaptic potassium currents before (i) and after (ii, red) application of DTX-I (left panel) or TsTX (right panel) and subsequent additions of MgTX (iii) at -20 mV are shown in the insets (superimposed) and in I-V relationships. Immunofluorescence signals of Kv channels that overlapped with synaptophysin signals were taken as presynaptic signals, and their averaged intensities were determined by densitometric measurements (filled columns). www.jneurosci.org /cgi/content/full/23/32/10445   (5580 words)

Heterogeneous Presynaptic Release Probabilities: Functional Relevance for Short-Term Plasticity -- Trommershäuser et al. 84 (3): 1563 -- Biophysical Journal We assume that buffer is present in the presynaptic terminal Upon presynaptic stimulation vesicles are released from two different pools that differ regarding their release probability and timescales of recruitment. FIGURE 2  Effect of elevations in presynaptic Ca concentration on release probability and local Ca concentrations. www.biophysj.org /cgi/content/full/84/3/1563   (6762 words)

Urban Entomology [Ebeling Chap. 9 part 3] Pests Attacking Mand and His Pets Salivary secretions of the ticks cause a neuromuscular block, presumably at the presynaptic terminal fibers of somatic motor axones, which results in the failure of release of acetylcholine. Invertebrates are commonly paralyzed by arthropod venoms, but apparently the only parallel phenomenon in vertebrates is the paralysis caused by the bites of wood ticks. www.entomology.ucr.edu /ebeling/ebel9-3.html   (19692 words)

SNARE Docking: Vesicles move toward and interact with membrane of presynaptic terminal : Presynaptic cytoskeletal matrix; Role in cycling of synaptic vesicles PRESYNAPTIC PROTEINS, SYNAPTIC VESICLE DOCKING and MEMBRANE FUSION www.neuro.wustl.edu /neuromuscular/pathol/snare.htm   (959 words)

Myasthenic Syndromes Reduced numbers of P/Q Ca channels on presynaptic terminals Probable mechanism: Reduced acetylcholine resynthesis or repackaging in presynaptic terminal Presynaptic: Number of quanta released by nerve impulse www.neuro.wustl.edu /neuromuscular/synmg.html   (2212 words)

Urban Entomology [Ebeling Chap. 9 part 3] Pests Attacking Mand and His Pets Salivary secretions of the ticks cause a neuromuscular block, presumably at the presynaptic terminal fibers of somatic motor axones, which results in the failure of release of acetylcholine. Shoshone Indian braves exposed their squaws to the "evil spirits" believed to be associated with gophers in the foothills of the Rockies, and the braves avoided areas shown by this pragmatic test to be inhabited by the evil spirits. In areas where chiggers are known to be a problem, the avoidance of their favored habitats is, of course, a way of minimizing infestation. www.entomology.ucr.edu /ebeling/ebel9-3.html   (19692 words)

A Ca2+-induced Ca2+ Release Mechanism Involved in Asynchronous Exocytosis at Frog Motor Nerve Terminals -- Narita et al. 112 (5): 593 -- The Journal of General Physiology Physiological significance of CICR in presynaptic terminals was Each data point is the average of those obtained from different terminals, whose number is shown above or below each point. Scanning of the nerve terminals was made by an x-y scan mode with or without the summation of two to four images. www.jgp.org /cgi/content/full/112/5/593   (19692 words)

Functional Coupling of Ca2+ Channels to Ryanodine Receptors at Presynaptic Terminals: Amplification of Exocytosis and Plasticity -- Narita et al. 115 (4): 519 -- The Journal of General Physiology terminals and amplify the impulse-evoked exocytosis and its Fluorescent images (right) were obtained by line scanning the nerve terminal loaded with dOGB-1 along the long axis of the nerve terminal with a confocal microscope in normal Ringer (20 images were averaged). rises in intracellular Ca in the terminals with little change www.jgp.org /cgi/content/full/115/4/519   (19692 words)

Differential Regulation of Transmitter Release by Presynaptic and Glial Ca2+ Internal Stores at the Neuromuscular Synapse -- Castonguay and Robitaille 21 (6): 1911 -- Journal of Neuroscience According to the dynamics of Ca entry and handling around an active zone in the nerve terminal and the local changes in presynaptic resting Ca level produced by tg, we propose that the ATPase pump is located in the membrane of synaptic vesicles located around release sites. The same measurements were made on Ca entry in nerve terminals elicited by a train of 10 pulses (100 Hz/100 msec). Note that tg did not cause any Ca elevation in the nerve terminal. www.jneurosci.org /cgi/content/full/21/6/1911   (19692 words)

The ubiquitin proteasome system in synaptic and axonal degeneration: a new twist to an old cycle -- Korhonen and Lindholm 165 (1): 27 -- The Journal of Cell Biology Intragenic deletion in the gene encoding ubiquitin carboxy-terminal hydrolase in gad mice. The ubiquitin proteasome system acutely regulates presynaptic protein turnover and synaptic efficacy. Mutant ubiquitin found in neurodegenerative disorders is a ubiquitin fusion degradation substrate that blocks proteasomal degradation. www.jcb.org /cgi/content/full/165/1/27   (19692 words)

Laboratory of Krys Bankiewicz - UCSF Department of Neurosurgery The goal of neurorestoration therapy is to restore function to degenerating dopaminergic neurons by preventing their death, restoring neurochemical biosynthetic capacity, and maintaining or regenerating presynaptic terminals in the striatum. In contrast to the pursuit of neurochemical augmentation strategies that aim to replace diminished dopamine stores that is characteristic of Parkinson's disease (PD), a second strategy to treat PD lies in the area of neurorestoration. Current evidence points to a variety of pathophysiologic processes that may contribute to neuronal degeneration (e.g., oxidative stress, mitochondrial dysfunction, exposure to environmental toxins) and that may represent future therapeutic targets. neurosurgery.medschool.ucsf.edu /neurosurgery_research/Movement/bankiewicz_lab.html   (19692 words)

vol5no1item3.html Heuser and Reese (1973) proposed, on the basis of experimental evidence, that the membranes of activated synaptic vesicles fuse with the membrane of the presynaptic terminal at the active zone (the region of the presynaptic terminal facing the synaptic cleft) and the vesicles discharge their contents into the synaptic cleft. Recent experiments and reviews indicate that both hypotheses are correct, each applying to a different pool of vesicles within the presynaptic terminal (Richards, Guatimosin, and Betz, 2000; Wilkinson and Cole, 2001). For almost thirty years there have been two competing hypotheses about how synaptic vesicles discharge transmitter molecules into the synapse and then are recycled for further activity. www.biopsychology.com /newsletters/vol5no1item3.html   (19692 words)

Therapy Information Services - Neuroscience Electrical synapses occur where the presynaptic terminal is in electrical continuity with the postsynaptic. Synapses are the junctions formed with other nerve cells where the presynaptic terminal of one cell comes into 'contact' with the postsynaptic membrane of another. The gap between the post- and presynaptic terminals is larger, and the mode of transmission is not electrical, but carried by neurotransmitters, neuroactive substances released at the presynaptic side of the junction. www.therapyedu.com /neuro/chap2.htm   (2170 words)

Cyberspace Presentation PRESYNAPTIC MEMBRANE is the membrane of a terminal button (or presynaptic button) in a synapse that lies adjacent to the postsynaptic synaptic membrane. POSTSYNAPTIC MEMBRANE is the cell membrane opposite the terminal button (presynaptic button) in a synapse. SYNAPTIC CLEFT is the space that separates pre- and postsynaptic neurons at chemical synapses. a.parsons.edu /~melissam/jthe_info2a.html   (2170 words)

SNP structure,function,disease: Analysis for ACHE GO:0042135 ==> The breakdown into simpler components of any of a group of substances that are released on excitation from the axon terminal of a presynaptic neuron of the central or peripheral nervous system and travel across the synaptic cleft to either excite or inhibit the target cell. At the tip of the nerve ending is the presynaptic membrane; facing it, and separated from it by a minute cleft (the synaptic cleft) is a specialized area of membrane on the receiving cell, known as the postsynaptic membrane. As the nerve fiber approaches the synapse it enlarges into a specialized structure, the presynaptic nerve ending, which contains mitochondria and synaptic vesicles. www.snps3d.org /modules.php?name=SnpAnalysis&locus_ac=43   (824 words)

synapse1 On the arrival of a nerve impulse at the terminal button, some the vesicles discharge their contents into the narrow cleft that separates the button from the membrane of another cell's dendrite, which is designated to receive the chemical message. In the synaptic process the transmitter substance is discharged into the synaptic cleft at the the synaptic junctions between neurons by vesicles that open up after fusing with the axon's presynaptic membrane, a process called exocytosis. When the nerve impulse reaches the synapse, a train of events is set in motion that culminates in the fusion of a vesicle with the presynaptic membrane and resulting release of acetylcholine into the cleft between the presynaptic and postsynaptic membranes, a process termed exocytosis. www.iprs.it /brainelsa/BACKUP_cd/schede/synapse.htm   (824 words)

R-Type Channels - A New Type Of Calcium Channels Controlling Signal Transduction Between Neurons In The Brain Because of the lack of the specific blocker, and the difficulty in directly accessing the small presynaptic terminals (a special compartment for a neuron to communicate with the other via neurotransmitters), it could not be addressed whether R-type channels are present in the presynaptic terminals. This technique provides a key to record and compare the electrical properties of the presynaptic calcium channels, and thus it became possible to address the question whether R-type channels are at the presynaptic terminal. About three years ago, Borst and Sakmann (Journal of Physiology (London) 489, 825-840, 1995) found that the electrical signals in both the pre- and the postsynaptic sides of a single synapse between neurons in the ventral coclear nucleus and the medial nucleus of the trapezoid body can be monitored simultaneously. www.eurekalert.org /pub_releases/1998-04/M-RCAN-290498.php   (824 words)

2. Nerve and Muscle Cells The fact that the impulse transfers across the synapse only in one direction, from the presynaptic terminal to the postsynaptic terminal, is due to the release of a chemical transmitter by the presynaptic cell. Experimentally determined conduction velocity of a nerve impulse in a mammalian myelinated axon as a function of the diameter. Conduction of a nerve impulse in a nerve axon. butler.cc.tut.fi /~malmivuo/bem/bembook/02/02.htm   (3465 words)

The Brain - Lesson 2, page 2 The released neurotransmitter, as well as any neurotransmitter that did not bind to a receptor, is either degraded by enzymes in the synaptic cleft or taken back up into the presynaptic axon terminal by active transport through a transporter or reuptake pump. Once the neurotransmitter is back inside the axon terminal, it is either destroyed or repackaged into new vesicles that may be released the next time the neuron is stimulated. After binding to the receptor, the neurotransmitter molecules either may be taken back up into the presynaptic neuron through the transporter molecules for repackaging into vesicles or may be degraded by enzymes present in the synaptic cleft. science.education.nih.gov /supplements/nih2/addiction/guide/lesson2-2.htm   (1464 words)

synapse1 In the synaptic process the transmitter substance is discharged into the synaptic cleft at the the synaptic junctions between neurons by vesicles that open up after fusing with the axon's presynaptic membrane, a process called exocytosis. On the arrival of a nerve impulse at the terminal button, some the vesicles discharge their contents into the narrow cleft that separates the button from the membrane of another cell's dendrite, which is designated to receive the chemical message. The characteristic synaptic vesicles can be readily recognized at each presynaptic region. www.iprs.it /brainelsa/BACKUP_cd/schede/synapse.htm   (1464 words)

Neurons The axon terminal is then the presynaptic terminal of a synapse. But it is that calcium that signals the vesicles to fuse (exocytosis) with the axon terminal and release their neurotransmitter into the synaptic cleft. The concept of this is same as for the electrical current for your toaster-- it starts at the plug in the wall, and runs all the way down the cord to the toaster itself. distance.stcc.edu /AandP/AP/AP1pages/nervssys/unit10/neurons.htm   (1464 words)

Stanford Encyclopedia article At electrical synapses, the current generated by the action potential at the presynaptic neuron flows directly into the postsynaptic cell, which is physically connected to the presynaptic terminal by a so-called gap junction. The notion of the “hard problem” of consciousness research refers to bridging the gap between first-person experience and third-person accounts of it. Grush, R., and Churchland, P.S. Gaps in Penrose's toilings. www.quantumconsciousness.org /StanfordEncyclopediaarticle.htm   (8846 words)

Lecture Notes, February 2-7, 2000 When an action potential is propagated to the synaptic terminal, depolarization of the terminal membrane (presynaptic membrane) opens voltage-dependent Ca channels increasing intracellular Ca The increase of Ca stimulates exocytosis of neurotransmitter that diffuses across the synaptic cleft to the postsynaptic membrane. The generator potential is a graded potential (like an EPSP) whose duration and magnitude is dependent on the strength and duration of the stimulus. The action potential is all or none, the duration and amplitude (overshoot) are invariant, they cannot be summed. www.spelman.edu /~biology/physiology/lectures/2_9.html   (1188 words)

5. Synapses, Receptor Cells, and Brain In this case an inhibitory nerve ending (from another axon known as the presynaptic inhibitor) is synapsed to an excitatory presynaptic terminal. In fact, the generator or receptor potentials cause repetitive firing of action pulses on the afferent neuron, and the firing rate (and rate of change) is reflective of the sensory input. Such a condition would alter the membrane potential from near the potassium Nernst potential to a value that approximates the average of the sodium and potassium equilibrium potentials. butler.cc.tut.fi /~malmivuo/bem/bembook/05/05.htm   (5278 words)

End Plate Although the ends of axons come close to the muscle fibers, they do not actually touch, and it is a chemical signal that bridges the gap between the axon terminal and the motor end plate. This neurotransmitter chemical (acetylcholine) is released from presynaptic vesicles when the nerve impulse reaches the end of the axon. This image shows a longitudinal view of several skeletal muscle fibers along with the terminal branches of the motor (efferent) nerve that innervates them. bioweb.uwlax.edu /aplab/Table_of_Contents/Lab_10/End_Plate/end_plate.html   (136 words)

Try your search on: Qwika (all wikis)

About us   |   Why use us?   |   Reviews   |   Press   |   Contact us   Copyright © 2005-2007 www.factbites.com Usage implies agreement with terms.