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PIP(2) alters of Ca(2+) currents in acutely dissociated supraoptic oxytocin neurons
Magnocellular neurosecretory cells (MNCs) occupying the supraoptic nucleus (SON) contain voltage‐gated Ca(2+) channels that provide Ca(2+) for triggering vesicle release, initiating signaling pathways, and activating channels, such as the potassium channels underlying the afterhyperpolarization (AHP...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
John Wiley and Sons Inc.
2019
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6708058/ https://www.ncbi.nlm.nih.gov/pubmed/31444865 http://dx.doi.org/10.14814/phy2.14198 |
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author | Kirchner, Matthew K. Armstrong, William E. Guan, Dongxu Ueta, Yoichi Foehring, Robert C. |
author_facet | Kirchner, Matthew K. Armstrong, William E. Guan, Dongxu Ueta, Yoichi Foehring, Robert C. |
author_sort | Kirchner, Matthew K. |
collection | PubMed |
description | Magnocellular neurosecretory cells (MNCs) occupying the supraoptic nucleus (SON) contain voltage‐gated Ca(2+) channels that provide Ca(2+) for triggering vesicle release, initiating signaling pathways, and activating channels, such as the potassium channels underlying the afterhyperpolarization (AHP). Phosphotidylinositol 4,5‐bisphosphate (PIP(2)) is a phospholipid membrane component that has been previously shown to modulate Ca(2+) channels, including in the SON in our previous work. In this study, we further investigated the ways in which PIP(2) modulates these channels, and for the first time show how PIP(2) modulates Ca(V) channel currents in native membranes. Using whole cell patch clamp of genetically labeled dissociated neurons, we demonstrate that PIP(2) depletion via wortmannin (0.5 μmol/L) inhibits Ca(2+) channel currents in OT but not VP neurons. Additionally, it hyperpolarizes voltage‐dependent activation of the channels by ~5 mV while leaving the slope of activation unchanged, properties unaffected in VP neurons. We also identified key differences in baseline currents between the cell types, wherein VP whole cell Ca(2+) currents display more inactivation and shorter deactivation time constants. Wortmannin accelerates inactivation of Ca(2+) channels in OT neurons, which we show to be mostly an effect on N‐type Ca(2+) channels. Finally, we demonstrate that wortmannin prevents prepulse‐induced facilitation of peak Ca(2+) channel currents. We conclude that PIP(2) is a modulator that enhances current through N‐type channels. This has implications for the afterhyperpolarization (AHP) of OT neurons, as previous work from our laboratory demonstrated the AHP is inhibited by wortmannin, and that its primary activation is from intracellular Ca(2+) contributed by N‐type channels. |
format | Online Article Text |
id | pubmed-6708058 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2019 |
publisher | John Wiley and Sons Inc. |
record_format | MEDLINE/PubMed |
spelling | pubmed-67080582019-08-28 PIP(2) alters of Ca(2+) currents in acutely dissociated supraoptic oxytocin neurons Kirchner, Matthew K. Armstrong, William E. Guan, Dongxu Ueta, Yoichi Foehring, Robert C. Physiol Rep Original Research Magnocellular neurosecretory cells (MNCs) occupying the supraoptic nucleus (SON) contain voltage‐gated Ca(2+) channels that provide Ca(2+) for triggering vesicle release, initiating signaling pathways, and activating channels, such as the potassium channels underlying the afterhyperpolarization (AHP). Phosphotidylinositol 4,5‐bisphosphate (PIP(2)) is a phospholipid membrane component that has been previously shown to modulate Ca(2+) channels, including in the SON in our previous work. In this study, we further investigated the ways in which PIP(2) modulates these channels, and for the first time show how PIP(2) modulates Ca(V) channel currents in native membranes. Using whole cell patch clamp of genetically labeled dissociated neurons, we demonstrate that PIP(2) depletion via wortmannin (0.5 μmol/L) inhibits Ca(2+) channel currents in OT but not VP neurons. Additionally, it hyperpolarizes voltage‐dependent activation of the channels by ~5 mV while leaving the slope of activation unchanged, properties unaffected in VP neurons. We also identified key differences in baseline currents between the cell types, wherein VP whole cell Ca(2+) currents display more inactivation and shorter deactivation time constants. Wortmannin accelerates inactivation of Ca(2+) channels in OT neurons, which we show to be mostly an effect on N‐type Ca(2+) channels. Finally, we demonstrate that wortmannin prevents prepulse‐induced facilitation of peak Ca(2+) channel currents. We conclude that PIP(2) is a modulator that enhances current through N‐type channels. This has implications for the afterhyperpolarization (AHP) of OT neurons, as previous work from our laboratory demonstrated the AHP is inhibited by wortmannin, and that its primary activation is from intracellular Ca(2+) contributed by N‐type channels. John Wiley and Sons Inc. 2019-08-23 /pmc/articles/PMC6708058/ /pubmed/31444865 http://dx.doi.org/10.14814/phy2.14198 Text en © 2019 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Original Research Kirchner, Matthew K. Armstrong, William E. Guan, Dongxu Ueta, Yoichi Foehring, Robert C. PIP(2) alters of Ca(2+) currents in acutely dissociated supraoptic oxytocin neurons |
title | PIP(2) alters of Ca(2+) currents in acutely dissociated supraoptic oxytocin neurons |
title_full | PIP(2) alters of Ca(2+) currents in acutely dissociated supraoptic oxytocin neurons |
title_fullStr | PIP(2) alters of Ca(2+) currents in acutely dissociated supraoptic oxytocin neurons |
title_full_unstemmed | PIP(2) alters of Ca(2+) currents in acutely dissociated supraoptic oxytocin neurons |
title_short | PIP(2) alters of Ca(2+) currents in acutely dissociated supraoptic oxytocin neurons |
title_sort | pip(2) alters of ca(2+) currents in acutely dissociated supraoptic oxytocin neurons |
topic | Original Research |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6708058/ https://www.ncbi.nlm.nih.gov/pubmed/31444865 http://dx.doi.org/10.14814/phy2.14198 |
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