Terrestrial apnoeas and the development of cardiac control in Australian fur seal (Arctocephalus pusillus doriferus) pups

The development of cardiac control in association with terrestrial respiration patterns was examined throughout the period of maternal dependence in Australian fur seal pups. Resting eupnoic heart rate and respiration rate were significantly correlated (r 2 = 0.49) and both decreased with age (P <...

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Bibliographic Details
Main Authors: N Deacon, John Arnould
Format: Other Non-Article Part of Journal/Newspaper
Language:unknown
Published: 2009
Subjects:
Physiology
Zoology
Fur seal
Bradycardia
Development
Science & Technology
Life Sciences & Biomedicine
NORTHERN ELEPHANT SEALS
BODY OXYGEN STORES
HEART-RATE
DIVING MAMMALS
WEDDELL SEALS
HARBOR SEALS
MIROUNGA-ANGUSTIROSTRIS
ZALOPHUS-CALIFORNIANUS
PHOCA-VITULINA
DIVE BEHAVIOR
Weddell
Elephant Seals
Phoca vitulina
Weddell Seals
Online Access:http://hdl.handle.net/10536/DRO/DU:30028558
https://figshare.com/articles/journal_contribution/Terrestrial_apnoeas_and_the_development_of_cardiac_control_in_Australian_fur_seal_Arctocephalus_pusillus_doriferus_pups/21032206
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Summary:The development of cardiac control in association with terrestrial respiration patterns was examined throughout the period of maternal dependence in Australian fur seal pups. Resting eupnoic heart rate and respiration rate were significantly correlated (r 2 = 0.49) and both decreased with age (P < 0.05 in both cases). From an early age (1 month), pups displayed terrestrial apnoeas (18.1 ± 0.5 s) accompanied by substantial bradycardia (127 beats min -1 , a 13% decrease from eupnoic HR). Terrestrial apnoea duration increased significantly with age reaching a mean of 41 s just prior to weaning, slightly lower than the mean dive duration (52 s) previously recorded for pups of the same age. Correspondingly, mean apnoic heart rate decreased with age to 74 beats min -1 just prior to weaning, representing a 25% decrease on eupnoic heart rate. Importantly, concomitant with the decrease in mean apnoic heart rate with age, an increase in the control of bradycardia was evident with the variability in instantaneous apnoic heart decreasing such that older pups were able to maintain a low steady heart rate for the duration of the apnoea. The changes seen in these parameters are similar to those reported during postnatal development in elephant seals ( Mirounga spp.) and harbour seals ( Phoca vitulina ), and are considered indicative of the development of cardiac control. These findings suggest a common strategy for the development of bradycardia control in both otariid and phocid seals.

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