Specialized impulse conduction pathway in the alligator heart
Mammals and birds have a specialized cardiac atrioventricular conduction system enabling rapid activation of both ventricles. This system may have evolved together with high heart rates to support their endothermic state (warm-bloodedness) and is seemingly lacking in ectothermic vertebrates from whi...
| Main Authors: | , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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eLife Sciences Publications Ltd
2018-03-01
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| Series: | eLife |
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| Online Access: | https://elifesciences.org/articles/32120 |
| _version_ | 1811236878896070656 |
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| author | Bjarke Jensen Bastiaan J Boukens Dane A Crossley II Justin Conner Rajiv A Mohan Karel van Duijvenboden Alex V Postma Christopher R Gloschat Ruth M Elsey David Sedmera Igor R Efimov Vincent M Christoffels |
| author_facet | Bjarke Jensen Bastiaan J Boukens Dane A Crossley II Justin Conner Rajiv A Mohan Karel van Duijvenboden Alex V Postma Christopher R Gloschat Ruth M Elsey David Sedmera Igor R Efimov Vincent M Christoffels |
| author_sort | Bjarke Jensen |
| collection | DOAJ |
| description | Mammals and birds have a specialized cardiac atrioventricular conduction system enabling rapid activation of both ventricles. This system may have evolved together with high heart rates to support their endothermic state (warm-bloodedness) and is seemingly lacking in ectothermic vertebrates from which first mammals then birds independently evolved. Here, we studied the conduction system in crocodiles (Alligator mississippiensis), the only ectothermic vertebrates with a full ventricular septum. We identified homologues of mammalian conduction system markers (Tbx3-Tbx5, Scn5a, Gja5, Nppa-Nppb) and show the presence of a functional atrioventricular bundle. The ventricular Purkinje network, however, was absent and slow ventricular conduction relied on trabecular myocardium, as it does in other ectothermic vertebrates. We propose the evolution of the atrioventricular bundle followed full ventricular septum formation prior to the development of high heart rates and endothermy. In contrast, the evolution of the ventricular Purkinje network is strongly associated with high heart rates and endothermy. |
| first_indexed | 2024-04-12T12:15:43Z |
| format | Article |
| id | doaj.art-5fcfe392352d4541a30312ae3ea07766 |
| institution | Directory Open Access Journal |
| issn | 2050-084X |
| language | English |
| last_indexed | 2024-04-12T12:15:43Z |
| publishDate | 2018-03-01 |
| publisher | eLife Sciences Publications Ltd |
| record_format | Article |
| series | eLife |
| spelling | doaj.art-5fcfe392352d4541a30312ae3ea077662022-12-22T03:33:26ZengeLife Sciences Publications LtdeLife2050-084X2018-03-01710.7554/eLife.32120Specialized impulse conduction pathway in the alligator heartBjarke Jensen0https://orcid.org/0000-0002-7750-8035Bastiaan J Boukens1Dane A Crossley II2Justin Conner3Rajiv A Mohan4https://orcid.org/0000-0002-3622-1759Karel van Duijvenboden5Alex V Postma6Christopher R Gloschat7Ruth M Elsey8David Sedmera9Igor R Efimov10https://orcid.org/0000-0002-1483-5039Vincent M Christoffels11https://orcid.org/0000-0003-4131-2636Department of Medical Biology, Heart Failure Research Center, Academic Medical Center, University of Amsterdam, Amsterdam, The NetherlandsDepartment of Medical Biology, Heart Failure Research Center, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Department of Biomedical Engineering, George Washington University, Washington, DC, United StatesDepartment of Biological Sciences, University of North Texas, Denton, United StatesDepartment of Biological Sciences, University of North Texas, Denton, United StatesDepartment of Medical Biology, Heart Failure Research Center, Academic Medical Center, University of Amsterdam, Amsterdam, The NetherlandsDepartment of Medical Biology, Heart Failure Research Center, Academic Medical Center, University of Amsterdam, Amsterdam, The NetherlandsDepartment of Medical Biology, Heart Failure Research Center, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Department of Clinical Genetics, Academic Medical Center, University of Amsterdam, Amsterdam, The NetherlandsDepartment of Biomedical Engineering, George Washington University, Washington, DC, United StatesRockefeller Wildlife Refuge, Louisiana Department of Wildlife and Fisheries, Grand Chenier, United StatesInstitute of Anatomy, First Medical Faculty, Charles University, and Institute of Physiology, Czech Academy of Sciences, Prague, Czech RepublicDepartment of Biomedical Engineering, George Washington University, Washington, DC, United StatesDepartment of Medical Biology, Heart Failure Research Center, Academic Medical Center, University of Amsterdam, Amsterdam, The NetherlandsMammals and birds have a specialized cardiac atrioventricular conduction system enabling rapid activation of both ventricles. This system may have evolved together with high heart rates to support their endothermic state (warm-bloodedness) and is seemingly lacking in ectothermic vertebrates from which first mammals then birds independently evolved. Here, we studied the conduction system in crocodiles (Alligator mississippiensis), the only ectothermic vertebrates with a full ventricular septum. We identified homologues of mammalian conduction system markers (Tbx3-Tbx5, Scn5a, Gja5, Nppa-Nppb) and show the presence of a functional atrioventricular bundle. The ventricular Purkinje network, however, was absent and slow ventricular conduction relied on trabecular myocardium, as it does in other ectothermic vertebrates. We propose the evolution of the atrioventricular bundle followed full ventricular septum formation prior to the development of high heart rates and endothermy. In contrast, the evolution of the ventricular Purkinje network is strongly associated with high heart rates and endothermy.https://elifesciences.org/articles/32120American alligatorconduction systemevolutionVentricular septumTbx3 |
| spellingShingle | Bjarke Jensen Bastiaan J Boukens Dane A Crossley II Justin Conner Rajiv A Mohan Karel van Duijvenboden Alex V Postma Christopher R Gloschat Ruth M Elsey David Sedmera Igor R Efimov Vincent M Christoffels Specialized impulse conduction pathway in the alligator heart eLife American alligator conduction system evolution Ventricular septum Tbx3 |
| title | Specialized impulse conduction pathway in the alligator heart |
| title_full | Specialized impulse conduction pathway in the alligator heart |
| title_fullStr | Specialized impulse conduction pathway in the alligator heart |
| title_full_unstemmed | Specialized impulse conduction pathway in the alligator heart |
| title_short | Specialized impulse conduction pathway in the alligator heart |
| title_sort | specialized impulse conduction pathway in the alligator heart |
| topic | American alligator conduction system evolution Ventricular septum Tbx3 |
| url | https://elifesciences.org/articles/32120 |
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