| The development of diving bradycardia in bottlenose dolphins (Tursiops truncatus). | |
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MedLine Citation:
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PMID: 14639484 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Bradycardia is an important component of the dive response, yet little is known about this response in immature marine mammals. To determine if diving bradycardia improves with age, cardiac patterns from trained immature and mature bottlenose dolphins ( Tursiops truncatus) were recorded during three conditions (stationary respiration, voluntary breath-hold, and shallow diving). Maximum (mean: 117+/-1 beats.min(-1)) and resting (mean: 101+/-5 beats.min(-1)) heart rate (HR) at the water surface were similar regardless of age. All dolphins lowered HR in response to apnea; mean steady state breath-hold HR was not correlated with age. However, the ability to reduce HR while diving improved with age. Minimum and mean steady state HR during diving were highest for calves. For example, 1.5-3.5-year-old calves had significantly higher mean steady state diving HR (51+/-1 beats.min(-1)) than 3.5-5.5-year-old juveniles (44+/-1 beats.min(-1)). As a result, older dolphins demonstrated greater overall reductions in HR during diving. Longitudinal studies concur; the ability to reduce HR improved as individual calves matured. Thus, although newly weaned calves as young as 1.7 years exhibit elements of cardiac control, the capacity to reduce HR while diving improves with maturation up to 3.5 years postpartum. Limited ability for bradycardia may partially explain the short dive durations observed for immature marine mammals. |
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Authors:
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S R Noren; V Cuccurullo; T M Williams |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S. Date: 2003-11-25 |
Journal Detail:
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Title: Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology Volume: 174 ISSN: 0174-1578 ISO Abbreviation: J. Comp. Physiol. B, Biochem. Syst. Environ. Physiol. Publication Date: 2004 Mar |
Date Detail:
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Created Date: 2004-03-04 Completed Date: 2004-11-10 Revised Date: 2009-06-08 |
Medline Journal Info:
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Nlm Unique ID: 8413200 Medline TA: J Comp Physiol B Country: Germany |
Other Details:
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Languages: eng Pagination: 139-47 Citation Subset: IM |
Affiliation:
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Ecology and Evolutionary Biology Department, Center for Ocean Health, University of California, Santa Cruz, CA 95060, USA. snoren@biology.ucsc.edu |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Age Factors Animals Bradycardia / etiology, physiopathology Diving / physiology* Dolphins / growth & development, physiology* Heart Rate / physiology Respiratory Physiological Phenomena |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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