5-hydroxytryptamine (5-HT) cellular sequestration during chronic exposure delays 5-HT3 receptor resensitization due to Its subsequent release

J. Daniel Hothersall, Amy Alexander, Andrew J. Samson, Christopher Moffat, Karen A. Bollan, Christopher N. Connolly (Lead / Corresponding author)

    Research output: Contribution to journalArticle

    2 Citations (Scopus)
    82 Downloads (Pure)

    Abstract

    The serotonergic synapse is dynamically regulated by serotonin (5-hydroxytryptamine (5-HT)) with elevated levels leading to the down-regulation of the serotonin transporter and a variety of 5-HT receptors, including the 5-HT type-3 (5-HT3) receptors. We report that recombinantly expressed 5-HT3 receptor binding sites are reduced by chronic exposure to 5-HT (IC50 of 154.0 ± 45.7 μm, t½ = 28.6 min). This is confirmed for 5-HT3 receptor-induced contractions in the guinea pig ileum, which are down-regulated after chronic, but not acute, exposure to 5-HT. The loss of receptor function does not involve endocytosis, and surface receptor levels are unaltered. The rate and extent of down-regulation is potentiated by serotonin transporter function (IC50 of 2.3 ± 1.0 μm, t½ = 3.4 min). Interestingly, the level of 5-HT uptake correlates with the extent of down-regulation. Using TX-114 extraction, we find that accumulated 5-HT remains soluble and not membrane-bound. This cytoplasmically sequestered 5-HT is readily releasable from both COS-7 cells and the guinea pig ileum. Moreover, the 5-HT level released is sufficient to prevent recovery from receptor desensitization in the guinea pig ileum. Together, these findings suggest the existence of a novel mechanism of down-regulation where the chronic release of sequestered 5-HT prolongs receptor desensitization.
    Original languageEnglish
    Pages (from-to)32020-32029
    Number of pages10
    JournalJournal of Biological Chemistry
    Volume289
    Issue number46
    DOIs
    Publication statusPublished - 14 Nov 2014

    Fingerprint

    Serotonin Receptors
    Serotonin
    Down-Regulation
    Ileum
    Serotonin Plasma Membrane Transport Proteins
    Guinea Pigs
    Inhibitory Concentration 50
    Receptors, Serotonin, 5-HT3
    COS Cells
    Endocytosis
    Synapses
    Binding Sites
    Membranes
    Recovery

    Cite this

    Hothersall, J. Daniel ; Alexander, Amy ; Samson, Andrew J. ; Moffat, Christopher ; Bollan, Karen A. ; Connolly, Christopher N. / 5-hydroxytryptamine (5-HT) cellular sequestration during chronic exposure delays 5-HT3 receptor resensitization due to Its subsequent release. In: Journal of Biological Chemistry. 2014 ; Vol. 289, No. 46. pp. 32020-32029.
    @article{10932e8e753a46c3b3efae79613c3fb7,
    title = "5-hydroxytryptamine (5-HT) cellular sequestration during chronic exposure delays 5-HT3 receptor resensitization due to Its subsequent release",
    abstract = "The serotonergic synapse is dynamically regulated by serotonin (5-hydroxytryptamine (5-HT)) with elevated levels leading to the down-regulation of the serotonin transporter and a variety of 5-HT receptors, including the 5-HT type-3 (5-HT3) receptors. We report that recombinantly expressed 5-HT3 receptor binding sites are reduced by chronic exposure to 5-HT (IC50 of 154.0 ± 45.7 μm, t½ = 28.6 min). This is confirmed for 5-HT3 receptor-induced contractions in the guinea pig ileum, which are down-regulated after chronic, but not acute, exposure to 5-HT. The loss of receptor function does not involve endocytosis, and surface receptor levels are unaltered. The rate and extent of down-regulation is potentiated by serotonin transporter function (IC50 of 2.3 ± 1.0 μm, t½ = 3.4 min). Interestingly, the level of 5-HT uptake correlates with the extent of down-regulation. Using TX-114 extraction, we find that accumulated 5-HT remains soluble and not membrane-bound. This cytoplasmically sequestered 5-HT is readily releasable from both COS-7 cells and the guinea pig ileum. Moreover, the 5-HT level released is sufficient to prevent recovery from receptor desensitization in the guinea pig ileum. Together, these findings suggest the existence of a novel mechanism of down-regulation where the chronic release of sequestered 5-HT prolongs receptor desensitization.",
    author = "Hothersall, {J. Daniel} and Amy Alexander and Samson, {Andrew J.} and Christopher Moffat and Bollan, {Karen A.} and Connolly, {Christopher N.}",
    note = "Copyright {\circledC} 2014, The American Society for Biochemistry and Molecular Biology.",
    year = "2014",
    month = "11",
    day = "14",
    doi = "10.1074/jbc.M114.594796",
    language = "English",
    volume = "289",
    pages = "32020--32029",
    journal = "Journal of Biological Chemistry",
    issn = "0021-9258",
    publisher = "American Society for Biochemistry and Molecular Biology",
    number = "46",

    }

    5-hydroxytryptamine (5-HT) cellular sequestration during chronic exposure delays 5-HT3 receptor resensitization due to Its subsequent release. / Hothersall, J. Daniel; Alexander, Amy; Samson, Andrew J.; Moffat, Christopher; Bollan, Karen A.; Connolly, Christopher N. (Lead / Corresponding author).

    In: Journal of Biological Chemistry, Vol. 289, No. 46, 14.11.2014, p. 32020-32029.

    Research output: Contribution to journalArticle

    TY - JOUR

    T1 - 5-hydroxytryptamine (5-HT) cellular sequestration during chronic exposure delays 5-HT3 receptor resensitization due to Its subsequent release

    AU - Hothersall, J. Daniel

    AU - Alexander, Amy

    AU - Samson, Andrew J.

    AU - Moffat, Christopher

    AU - Bollan, Karen A.

    AU - Connolly, Christopher N.

    N1 - Copyright © 2014, The American Society for Biochemistry and Molecular Biology.

    PY - 2014/11/14

    Y1 - 2014/11/14

    N2 - The serotonergic synapse is dynamically regulated by serotonin (5-hydroxytryptamine (5-HT)) with elevated levels leading to the down-regulation of the serotonin transporter and a variety of 5-HT receptors, including the 5-HT type-3 (5-HT3) receptors. We report that recombinantly expressed 5-HT3 receptor binding sites are reduced by chronic exposure to 5-HT (IC50 of 154.0 ± 45.7 μm, t½ = 28.6 min). This is confirmed for 5-HT3 receptor-induced contractions in the guinea pig ileum, which are down-regulated after chronic, but not acute, exposure to 5-HT. The loss of receptor function does not involve endocytosis, and surface receptor levels are unaltered. The rate and extent of down-regulation is potentiated by serotonin transporter function (IC50 of 2.3 ± 1.0 μm, t½ = 3.4 min). Interestingly, the level of 5-HT uptake correlates with the extent of down-regulation. Using TX-114 extraction, we find that accumulated 5-HT remains soluble and not membrane-bound. This cytoplasmically sequestered 5-HT is readily releasable from both COS-7 cells and the guinea pig ileum. Moreover, the 5-HT level released is sufficient to prevent recovery from receptor desensitization in the guinea pig ileum. Together, these findings suggest the existence of a novel mechanism of down-regulation where the chronic release of sequestered 5-HT prolongs receptor desensitization.

    AB - The serotonergic synapse is dynamically regulated by serotonin (5-hydroxytryptamine (5-HT)) with elevated levels leading to the down-regulation of the serotonin transporter and a variety of 5-HT receptors, including the 5-HT type-3 (5-HT3) receptors. We report that recombinantly expressed 5-HT3 receptor binding sites are reduced by chronic exposure to 5-HT (IC50 of 154.0 ± 45.7 μm, t½ = 28.6 min). This is confirmed for 5-HT3 receptor-induced contractions in the guinea pig ileum, which are down-regulated after chronic, but not acute, exposure to 5-HT. The loss of receptor function does not involve endocytosis, and surface receptor levels are unaltered. The rate and extent of down-regulation is potentiated by serotonin transporter function (IC50 of 2.3 ± 1.0 μm, t½ = 3.4 min). Interestingly, the level of 5-HT uptake correlates with the extent of down-regulation. Using TX-114 extraction, we find that accumulated 5-HT remains soluble and not membrane-bound. This cytoplasmically sequestered 5-HT is readily releasable from both COS-7 cells and the guinea pig ileum. Moreover, the 5-HT level released is sufficient to prevent recovery from receptor desensitization in the guinea pig ileum. Together, these findings suggest the existence of a novel mechanism of down-regulation where the chronic release of sequestered 5-HT prolongs receptor desensitization.

    UR - http://www.scopus.com/inward/record.url?scp=84911164054&partnerID=8YFLogxK

    U2 - 10.1074/jbc.M114.594796

    DO - 10.1074/jbc.M114.594796

    M3 - Article

    C2 - 25281748

    VL - 289

    SP - 32020

    EP - 32029

    JO - Journal of Biological Chemistry

    JF - Journal of Biological Chemistry

    SN - 0021-9258

    IS - 46

    ER -