Heart rate changes and myocardial sodium
Abstract Historic studies with sodium ion (Na+) micropipettes and first‐generation fluorescent probes suggested that an increase in heart rate results in higher intracellular Na+‐levels. Using a dual fluorescence indicator approach, we simultaneously assessed the dynamic changes in intracellular Na+...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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Wiley
2022-09-01
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| Series: | Physiological Reports |
| Subjects: | |
| Online Access: | https://doi.org/10.14814/phy2.15446 |
| _version_ | 1797397152744341504 |
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| author | Gabrielle Nelson Bo Ye Morgan Schock Daniel L. Lustgarten Elisabeth K. Mayhew Bradley M. Palmer Markus Meyer |
| author_facet | Gabrielle Nelson Bo Ye Morgan Schock Daniel L. Lustgarten Elisabeth K. Mayhew Bradley M. Palmer Markus Meyer |
| author_sort | Gabrielle Nelson |
| collection | DOAJ |
| description | Abstract Historic studies with sodium ion (Na+) micropipettes and first‐generation fluorescent probes suggested that an increase in heart rate results in higher intracellular Na+‐levels. Using a dual fluorescence indicator approach, we simultaneously assessed the dynamic changes in intracellular Na+ and calcium (Ca2+) with measures of force development in isolated excitable myocardial strip preparations from rat and human left ventricular myocardium at different stimulation rates and modeled the Na+‐effects on the sodium‐calcium exchanger (NCX). To gain further insight into the effects of heart rate on intracellular Na+‐regulation and sodium/potassium ATPase (NKA) function, Na+, and potassium ion (K+) levels were assessed in the coronary effluent (CE) of paced human subjects. Increasing the stimulation rate from 60/min to 180/min led to a transient Na+‐peak followed by a lower Na+‐level, whereas the return to 60/min had the opposite effect leading to a transient Na+‐trough followed by a higher Na+‐level. The presence of the Na+‐peak and trough suggests a delayed regulation of NKA activity in response to changes in heart rate. This was clinically confirmed in the pacing study where CE‐K+ levels were raised above steady‐state levels with rapid pacing and reduced after pacing cessation. Despite an initial Na+ peak that is due to a delayed increase in NKA activity, an increase in heart rate was associated with lower, and not higher, Na+‐levels in the myocardium. The dynamic changes in Na+ unveil the adaptive role of NKA to maintain Na+ and K+‐gradients that preserve membrane potential and cellular Ca2+‐hemostasis. |
| first_indexed | 2024-03-09T01:05:50Z |
| format | Article |
| id | doaj.art-90e5d2234c6b4890adacef0bbda6c674 |
| institution | Directory Open Access Journal |
| issn | 2051-817X |
| language | English |
| last_indexed | 2024-03-09T01:05:50Z |
| publishDate | 2022-09-01 |
| publisher | Wiley |
| record_format | Article |
| series | Physiological Reports |
| spelling | doaj.art-90e5d2234c6b4890adacef0bbda6c6742023-12-11T09:36:42ZengWileyPhysiological Reports2051-817X2022-09-011017n/an/a10.14814/phy2.15446Heart rate changes and myocardial sodiumGabrielle Nelson0Bo Ye1Morgan Schock2Daniel L. Lustgarten3Elisabeth K. Mayhew4Bradley M. Palmer5Markus Meyer6Department of Medicine Lillehei Heart Institute, University of Minnesota College of Medicine Minneapolis Minnesota USADepartment of Medicine Lillehei Heart Institute, University of Minnesota College of Medicine Minneapolis Minnesota USADepartment of Medicine Lillehei Heart Institute, University of Minnesota College of Medicine Minneapolis Minnesota USADepartment of Medicine and Physiology University of Vermont Larner College of Medicine Burlington Vermont USADepartment of Medicine and Physiology University of Vermont Larner College of Medicine Burlington Vermont USADepartment of Medicine and Physiology University of Vermont Larner College of Medicine Burlington Vermont USADepartment of Medicine Lillehei Heart Institute, University of Minnesota College of Medicine Minneapolis Minnesota USAAbstract Historic studies with sodium ion (Na+) micropipettes and first‐generation fluorescent probes suggested that an increase in heart rate results in higher intracellular Na+‐levels. Using a dual fluorescence indicator approach, we simultaneously assessed the dynamic changes in intracellular Na+ and calcium (Ca2+) with measures of force development in isolated excitable myocardial strip preparations from rat and human left ventricular myocardium at different stimulation rates and modeled the Na+‐effects on the sodium‐calcium exchanger (NCX). To gain further insight into the effects of heart rate on intracellular Na+‐regulation and sodium/potassium ATPase (NKA) function, Na+, and potassium ion (K+) levels were assessed in the coronary effluent (CE) of paced human subjects. Increasing the stimulation rate from 60/min to 180/min led to a transient Na+‐peak followed by a lower Na+‐level, whereas the return to 60/min had the opposite effect leading to a transient Na+‐trough followed by a higher Na+‐level. The presence of the Na+‐peak and trough suggests a delayed regulation of NKA activity in response to changes in heart rate. This was clinically confirmed in the pacing study where CE‐K+ levels were raised above steady‐state levels with rapid pacing and reduced after pacing cessation. Despite an initial Na+ peak that is due to a delayed increase in NKA activity, an increase in heart rate was associated with lower, and not higher, Na+‐levels in the myocardium. The dynamic changes in Na+ unveil the adaptive role of NKA to maintain Na+ and K+‐gradients that preserve membrane potential and cellular Ca2+‐hemostasis.https://doi.org/10.14814/phy2.15446calciumheart ratepotassiumsodium |
| spellingShingle | Gabrielle Nelson Bo Ye Morgan Schock Daniel L. Lustgarten Elisabeth K. Mayhew Bradley M. Palmer Markus Meyer Heart rate changes and myocardial sodium Physiological Reports calcium heart rate potassium sodium |
| title | Heart rate changes and myocardial sodium |
| title_full | Heart rate changes and myocardial sodium |
| title_fullStr | Heart rate changes and myocardial sodium |
| title_full_unstemmed | Heart rate changes and myocardial sodium |
| title_short | Heart rate changes and myocardial sodium |
| title_sort | heart rate changes and myocardial sodium |
| topic | calcium heart rate potassium sodium |
| url | https://doi.org/10.14814/phy2.15446 |
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