Pharmacological Preconditioning Using Diazoxide Regulates Store-Operated Ca2 + Channels in Adult Rat Cardiomyocytes
Voltage-dependent Ca2+ channels and store-operated Ca2+ channels (SOCs) are the major routes of Ca2+ entry into mammalian cells. Previously, we reported that pharmacological preconditioning (PPC) leads to a decrease in the amplitude of L-type calcium channel current in the heart. In this study, we e...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2020-01-01
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| Series: | Frontiers in Physiology |
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| Online Access: | https://www.frontiersin.org/article/10.3389/fphys.2019.01589/full |
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| author | Raúl Sampieri Eridani Fuentes Elba D. Carrillo Ascención Hernández María C. García Jorge A. Sánchez |
| author_facet | Raúl Sampieri Eridani Fuentes Elba D. Carrillo Ascención Hernández María C. García Jorge A. Sánchez |
| author_sort | Raúl Sampieri |
| collection | DOAJ |
| description | Voltage-dependent Ca2+ channels and store-operated Ca2+ channels (SOCs) are the major routes of Ca2+ entry into mammalian cells. Previously, we reported that pharmacological preconditioning (PPC) leads to a decrease in the amplitude of L-type calcium channel current in the heart. In this study, we examined PPC-associated changes in SOC function. We measured adult cardiomyocyte membrane currents using the whole-cell patch-clamp technique, and we evaluated reactive oxygen species (ROS) production and intracellular Ca2+ levels in cardiomyocytes using fluorescent probes. Diazoxide (Dzx) and thapsigargin (Tg) were used to induce PPC and to deplete internal stores of Ca2+, respectively. Ca2+ store depletion generated inward currents with strong rectification, which were suppressed by the SOC blocker GSK-7975-A. These currents were completely abolished by PPC, an effect that could be countered with 5-hydroxydecanoate (5-HD; a selective mitochondrial ATP-sensitive K+ channel blocker), an intracellular mitochondrial energizing solution, or Ni2+ [a blocker of sodium–calcium exchanger (NCX)]. Buffering of ROS and intracellular Ca2+ also prevented PPC effects on SOC currents. Refilling of intracellular stores was largely suppressed by PPC, as determined by measuring intracellular Ca2+ with a fluorescent Ca2+ indicator. These results indicate that influx of Ca2+ through SOCs is inhibited by their ROS and Ca2+-dependent inactivation during PPC and that NCX is a likely source of PPC-inactivating Ca2+. We further showed that NCX associates with Orai1. Down-regulation of SOCs by PPC may play a role in cardioprotection following ischemia–reperfusion. |
| first_indexed | 2024-12-21T21:08:46Z |
| format | Article |
| id | doaj.art-c08dfd33eb9b4df592a97dd0bcdd9e14 |
| institution | Directory Open Access Journal |
| issn | 1664-042X |
| language | English |
| last_indexed | 2024-12-21T21:08:46Z |
| publishDate | 2020-01-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Physiology |
| spelling | doaj.art-c08dfd33eb9b4df592a97dd0bcdd9e142022-12-21T18:50:13ZengFrontiers Media S.A.Frontiers in Physiology1664-042X2020-01-011010.3389/fphys.2019.01589495726Pharmacological Preconditioning Using Diazoxide Regulates Store-Operated Ca2 + Channels in Adult Rat CardiomyocytesRaúl SampieriEridani FuentesElba D. CarrilloAscención HernándezMaría C. GarcíaJorge A. SánchezVoltage-dependent Ca2+ channels and store-operated Ca2+ channels (SOCs) are the major routes of Ca2+ entry into mammalian cells. Previously, we reported that pharmacological preconditioning (PPC) leads to a decrease in the amplitude of L-type calcium channel current in the heart. In this study, we examined PPC-associated changes in SOC function. We measured adult cardiomyocyte membrane currents using the whole-cell patch-clamp technique, and we evaluated reactive oxygen species (ROS) production and intracellular Ca2+ levels in cardiomyocytes using fluorescent probes. Diazoxide (Dzx) and thapsigargin (Tg) were used to induce PPC and to deplete internal stores of Ca2+, respectively. Ca2+ store depletion generated inward currents with strong rectification, which were suppressed by the SOC blocker GSK-7975-A. These currents were completely abolished by PPC, an effect that could be countered with 5-hydroxydecanoate (5-HD; a selective mitochondrial ATP-sensitive K+ channel blocker), an intracellular mitochondrial energizing solution, or Ni2+ [a blocker of sodium–calcium exchanger (NCX)]. Buffering of ROS and intracellular Ca2+ also prevented PPC effects on SOC currents. Refilling of intracellular stores was largely suppressed by PPC, as determined by measuring intracellular Ca2+ with a fluorescent Ca2+ indicator. These results indicate that influx of Ca2+ through SOCs is inhibited by their ROS and Ca2+-dependent inactivation during PPC and that NCX is a likely source of PPC-inactivating Ca2+. We further showed that NCX associates with Orai1. Down-regulation of SOCs by PPC may play a role in cardioprotection following ischemia–reperfusion.https://www.frontiersin.org/article/10.3389/fphys.2019.01589/fullOrai channelsSTIMSOCscardiomyocytepharmacological preconditioningdiazoxide |
| spellingShingle | Raúl Sampieri Eridani Fuentes Elba D. Carrillo Ascención Hernández María C. García Jorge A. Sánchez Pharmacological Preconditioning Using Diazoxide Regulates Store-Operated Ca2 + Channels in Adult Rat Cardiomyocytes Frontiers in Physiology Orai channels STIM SOCs cardiomyocyte pharmacological preconditioning diazoxide |
| title | Pharmacological Preconditioning Using Diazoxide Regulates Store-Operated Ca2 + Channels in Adult Rat Cardiomyocytes |
| title_full | Pharmacological Preconditioning Using Diazoxide Regulates Store-Operated Ca2 + Channels in Adult Rat Cardiomyocytes |
| title_fullStr | Pharmacological Preconditioning Using Diazoxide Regulates Store-Operated Ca2 + Channels in Adult Rat Cardiomyocytes |
| title_full_unstemmed | Pharmacological Preconditioning Using Diazoxide Regulates Store-Operated Ca2 + Channels in Adult Rat Cardiomyocytes |
| title_short | Pharmacological Preconditioning Using Diazoxide Regulates Store-Operated Ca2 + Channels in Adult Rat Cardiomyocytes |
| title_sort | pharmacological preconditioning using diazoxide regulates store operated ca2 channels in adult rat cardiomyocytes |
| topic | Orai channels STIM SOCs cardiomyocyte pharmacological preconditioning diazoxide |
| url | https://www.frontiersin.org/article/10.3389/fphys.2019.01589/full |
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