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Experimental Biology 1997 Symposium on Neurobiology of Thermoregulation: Role of Stress: EFFECT OF GENDER ON THERMOREGULATION AND SURVIVAL OF HYPOXIC RATS
Author(s) -
Wood Stephen C.,
Stabenau Erich K.
Publication year - 1998
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/j.1440-1681.1998.tb02196.x
Subject(s) - thermoregulation , hypothermia , hypoxia (environmental) , ketamine , anesthesia , medicine , cold stress , endocrinology , physiology , biology , chemistry , oxygen , biochemistry , organic chemistry , gene
SUMMARY 1. Hypothermia is a documented response to hypoxia but little is known about possible gender differences. Because female rats have a greater hypoxic ventilatory response than males, we hypothesized that females would be more tolerant of hypoxia. We studied 18 female and 18 male Long‐Evans rats. 2. Radiotelemetry transmitters for body temperature (Tb) were implanted under general anaesthesia (90 mg/mL ketamine and 10 mg/mL xylazine; 0.1 mL/100 g body weight, i.p.). 3. Rats were exposed to 21, 16, 12, 10, 8, 6, 4 and 2% O 2 (balance N 2 ) for 30 min each in chambers kept at either 31°C (clamped) or 20°C (hypothermic). Survival was defined as ataxic and unresponsive. 4. Females were more hypoxia tolerant than males, often enduring 2% inspired O 2 (13 km altitude). 5. This was correlated with a lower Tb in the hypothermic group, but not in the clamped group. 6. Hypothermia increased ‘survival’ of rats independent of gender. 7. When Tb was clamped, female rats showed significantly greater survival than males. 8. Thus, separate mechanisms (hypothermia or ventilation) may be acting to increase tolerance of clamped and hypothermic female rats to severe hypoxia.