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  1. Article: Extrasynaptic Communication.

    De-Miguel, Francisco F / Leon-Pinzon, Carolina / Torres-Platas, Susana G / Del-Pozo, Vanessa / Hernández-Mendoza, Guillermo A / Aguirre-Olivas, Dilia / Méndez, Bruno / Moore, Sharlen / Sánchez-Sugía, Celeste / García-Aguilera, Marco Antonio / Martínez-Valencia, Alejandro / Ramírez-Santiago, Guillermo / Rubí, J Miguel

    Frontiers in molecular neuroscience

    2021  Volume 14, Page(s) 638858

    Abstract: Streams of action potentials or long depolarizations evoke a massive exocytosis of transmitters and peptides from the surface of dendrites, axons and cell bodies of different neuron types. Such mode of exocytosis is known as extrasynaptic for occurring ... ...

    Abstract Streams of action potentials or long depolarizations evoke a massive exocytosis of transmitters and peptides from the surface of dendrites, axons and cell bodies of different neuron types. Such mode of exocytosis is known as extrasynaptic for occurring without utilization of synaptic structures. Most transmitters and all peptides can be released extrasynaptically. Neurons may discharge their contents with relative independence from the axon, soma and dendrites. Extrasynaptic exocytosis takes fractions of a second in varicosities or minutes in the soma or dendrites, but its effects last from seconds to hours. Unlike synaptic exocytosis, which is well localized, extrasynaptic exocytosis is diffuse and affects neuronal circuits, glia and blood vessels. Molecules that are liberated may reach extrasynaptic receptors microns away. The coupling between excitation and exocytosis follows a multistep mechanism, different from that at synapses, but similar to that for the release of hormones. The steps from excitation to exocytosis have been studied step by step for the vital transmitter serotonin in leech Retzius neurons. The events leading to serotonin exocytosis occur similarly for the release of other transmitters and peptides in central and peripheral neurons. Extrasynaptic exocytosis occurs commonly onto glial cells, which react by releasing the same or other transmitters. In the last section, we discuss how illumination of the retina evokes extrasynaptic release of dopamine and ATP. Dopamine contributes to light-adaptation; ATP activates glia, which mediates an increase in blood flow and oxygenation. A proper understanding of the workings of the nervous system requires the understanding of extrasynaptic communication.
    Language English
    Publishing date 2021-04-30
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2452967-9
    ISSN 1662-5099
    ISSN 1662-5099
    DOI 10.3389/fnmol.2021.638858
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Serotonin release from the neuronal cell body and its long-lasting effects on the nervous system.

    De-Miguel, Francisco F / Leon-Pinzon, Carolina / Noguez, Paula / Mendez, Bruno

    Philosophical transactions of the Royal Society of London. Series B, Biological sciences

    2015  Volume 370, Issue 1672

    Abstract: Serotonin, a modulator of multiple functions in the nervous system, is released predominantly extrasynaptically from neuronal cell bodies, axons and dendrites. This paper describes how serotonin is released from cell bodies of Retzius neurons in the ... ...

    Abstract Serotonin, a modulator of multiple functions in the nervous system, is released predominantly extrasynaptically from neuronal cell bodies, axons and dendrites. This paper describes how serotonin is released from cell bodies of Retzius neurons in the central nervous system (CNS) of the leech, and how it affects neighbouring glia and neurons. The large Retzius neurons contain serotonin packed in electrodense vesicles. Electrical stimulation with 10 impulses at 1 Hz fails to evoke exocytosis from the cell body, but the same number of impulses at 20 Hz promotes exocytosis via a multistep process. Calcium entry into the neuron triggers calcium-induced calcium release, which activates the transport of vesicle clusters to the plasma membrane. Exocytosis occurs there for several minutes. Serotonin that has been released activates autoreceptors that induce an inositol trisphosphate-dependent calcium increase, which produces further exocytosis. This positive feedback loop subsides when the last vesicles in the cluster fuse and calcium returns to basal levels. Serotonin released from the cell body is taken up by glia and released elsewhere in the CNS. Synchronous bursts of neuronal electrical activity appear minutes later and continue for hours. In this way, a brief train of impulses is translated into a long-term modulation in the nervous system.
    MeSH term(s) Animals ; Biological Transport, Active/physiology ; Calcium/metabolism ; Cell Body/metabolism ; Central Nervous System/cytology ; Central Nervous System/metabolism ; Central Nervous System/physiology ; Electric Stimulation ; Exocytosis/physiology ; Feedback, Physiological/physiology ; Leeches/physiology ; Models, Neurological ; Neurons/metabolism ; Serotonin/metabolism ; Transport Vesicles/metabolism
    Chemical Substances Serotonin (333DO1RDJY) ; Calcium (SY7Q814VUP)
    Language English
    Publishing date 2015-05-25
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 208382-6
    ISSN 1471-2970 ; 0080-4622 ; 0264-3839 ; 0962-8436
    ISSN (online) 1471-2970
    ISSN 0080-4622 ; 0264-3839 ; 0962-8436
    DOI 10.1098/rstb.2014.0196
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article: Somatic exocytosis of serotonin mediated by L-type calcium channels in cultured leech neurones.

    Trueta, Citlali / Méndez, Bruno / De-Miguel, Francisco F

    The Journal of physiology

    2003  Volume 547, Issue Pt 2, Page(s) 405–416

    Abstract: We studied somatic exocytosis of serotonin and its mediation by L-type calcium (Ca2+) channels in cultured Retzius neurones of the leech. Exocytosis was induced by trains of impulses at different frequencies or by depolarisation with 40 mM potassium (K+), ...

    Abstract We studied somatic exocytosis of serotonin and its mediation by L-type calcium (Ca2+) channels in cultured Retzius neurones of the leech. Exocytosis was induced by trains of impulses at different frequencies or by depolarisation with 40 mM potassium (K+), and was quantified by use of the fluorescent dye FM 1-43. Stimulation increased the membrane fluorescence and produced a pattern of FM 1-43 fluorescent spots of 1.28 +/- 0.01 microm in diameter, provided that Ca2+ was present in the bathing fluid. Individual spots lost their stain during depolarisation with 40 mM K+. Electron micrographs showed clusters of dense core vesicles, some of which were in contact with the cell membrane. Presynaptic structures with clear vesicles were absent from the soma. The number of fluorescent spots per soma, but not their diameter or their fluorescence intensity, depended on the frequency of stimulation. Trains at 1 Hz produced 19.5 +/- 5 spots per soma, 77.9 +/- 13.9 spots per soma were produced at 10 Hz and 91.5 +/- 16.9 spots per soma at 20 Hz. Staining patterns were similar for neurones in culture and in situ. In the presence of the L-type Ca2+ channel blocker nimodipine (10 microM), a 20 Hz train produced only 22.9 +/- 6.4 spots per soma, representing a 75 % reduction compared to control cells (P < 0.05). Subsequent incubation with 10 mM caffeine to induce Ca2+ release from intracellular stores increased the number of spots to 73.22 +/- 12.5. Blockers of N-, P-, Q- or invertebrate Ca2+ channels did not affect somatic exocytosis. Our results suggest that somatic exocytosis by neurones shares common mechanisms with excitable endocrine cells.
    MeSH term(s) Animals ; Calcium/metabolism ; Calcium Channels, L-Type/physiology ; Cells, Cultured ; Electric Stimulation ; Exocytosis/physiology ; Fluorescent Dyes ; Leeches ; Microscopy, Electron ; Neurons/physiology ; Neurons/ultrastructure ; Pyridinium Compounds ; Quaternary Ammonium Compounds ; Staining and Labeling
    Chemical Substances Calcium Channels, L-Type ; FM1 43 ; Fluorescent Dyes ; Pyridinium Compounds ; Quaternary Ammonium Compounds ; Calcium (SY7Q814VUP)
    Language English
    Publishing date 2003-03-01
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 3115-x
    ISSN 1469-7793 ; 0022-3751
    ISSN (online) 1469-7793
    ISSN 0022-3751
    DOI 10.1113/jphysiol.2002.030684
    Database MEDical Literature Analysis and Retrieval System OnLINE

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