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Profound metabolic depression in the hypoxia‐tolerant naked mole rat (879.2)
Author(s) -
Pamenter Matthew,
Dzal Yvonne,
Milsom William
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.879.2
Subject(s) - hypoxia (environmental) , medicine , endocrinology , hypoxic ventilatory response , torpor , hypothermia , biology , chemistry , respiratory system , oxygen , thermoregulation , organic chemistry
Naked mole rats (NMRs) are among the most hypoxia‐tolerant mammals identified. Metabolic depression is a common response to hypoxia and is associated with lowered body temperature and a reduced state of activity (e.g. torpor). Contrary to this, NMRs maintain body temperature and remain active during prolonged exposure to 3% O 2 . The physiological adaptations that enable NMRs to remain active and thrive in hypoxia are poorly understood and we asked whether hypoxia‐induced changes to metabolic, ventilatory, or cardiac homeostasis contribute to this tolerance. To examine this question we exposed NMRs to progressive hypoxic epochs of 21, 9, 7, 5, and 3% O 2 and measured metabolic rate, physical activity, ventilation, cardiac work, and body temperature. We found that NMRs exhibited profound metabolic depression (> 85%) at hypoxic levels < 7% O 2 , while maintaining body temperature and physical activity. Ventilation and heart rate increased with hypoxia but at a lower O 2 levels than in hypoxia‐intolerant animals. Metabolic depression was reversed by systemic injection of the adenosine receptor antagonist aminotheophylline. Following injection, exposure to 7% O 2 became lethal to animals that previously tolerated 3% O 2 without detriment. We conclude that the hypoxia‐tolerance of NMRs is dependent upon robust metabolic depression, which is mediated by a mechanism involving adenosine receptor activation. Grant Funding Source : NSERC