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Respiratory characteristics of the tammar wallaby pouch young and functional limitations in a newborn with skin gas exchange

Citation

MacFarlane, PM and Frappell, PB and Haase, T, Respiratory characteristics of the tammar wallaby pouch young and functional limitations in a newborn with skin gas exchange, Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology, 191 pp. 995-1006. ISSN 0174-1578 (2021) [Refereed Article]

Copyright Statement

© The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2021

DOI: doi:10.1007/s00360-021-01364-y

Abstract

A short gestation, low birth weight and presence of cutaneous exchange of O2 and CO2 comprise altricial features of newborn marsupials and that collectively implies a highly immature respiratory system. In the present study, we investigated various respiratory characteristics of the neonatal/postnatal tammar wallaby, a species of marsupial in which > 30% of the newborn’s total O2 demands are supported by cutaneous rather than pulmonary gas exchange. The ventilatory response (HVR) to acute hypoxia (10% inspired O2) was absent in the newborn (1 day old) pouch young; a hypoxic hypometabolism contributed entirely to the hyperventilation (increased pulmonary convection requirement). A high (compared to older animals) resting metabolic cost to breathe and an inefficient respiratory system suggest the lack of a HVR might be due to an energetic constraint that impinges on their ability to sustain an increase in ventilation. The latter was supported by the inability of the newborn to tolerate metabolic-ventilatory stimulation following administration of the metabolic uncoupler, 2,4-dinitrophenol (2,4-DNP). At 1 week of age, the cost of breathing was reduced, which coincided with the expression of a significant ventilatory response to hypoxia, a more energetically efficient respiratory system, and tolerance to 2,4-DNP. These data suggest this species of marsupial is born with major respiratory insufficiency, and that their pronounced dependence on the skin for metabolic gas exchange is of critical importance for survival.

Item Details

Item Type:Refereed Article
Keywords:metabolism, ventilation, breathing, hypoxia, newborn, marsupial
Research Division:Biological Sciences
Research Group:Biochemistry and cell biology
Research Field:Cell metabolism
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the biological sciences
UTAS Author:Frappell, PB (Professor Peter Frappell)
ID Code:146019
Year Published:2021
Web of Science® Times Cited:1
Deposited By:Ecology and Biodiversity
Deposited On:2021-08-18
Last Modified:2021-12-02
Downloads:0

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