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Sodium and Water Homeostasis During Chronic Intermittent Hypoxia in Female Rats
Author(s) -
HinojosaLaborde Carmen,
Craig Teresa,
HerreraRosales Myrna,
Tolstykh Olga,
Cunningham J. Thomas,
Mifflin Steve
Publication year - 2006
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.20.5.a1193-a
Subject(s) - sodium , hypoxia (environmental) , homeostasis , endocrinology , medicine , room air distribution , blood pressure , urine , zoology , chemistry , anesthesia , biology , oxygen , organic chemistry , physics , thermodynamics
Chronic intermittent hypoxia (CIH) is a widely used model for the repetitive bouts of hypoxia that occur during sleep apnea. Using this model we have demonstrated an elevation in blood pressure and disturbances in sodium and water homeostasis in male rats exposed to CIH. These previous findings indicate that the elevation of blood pressure is associated with sodium and water retention. We have also observed that female rats are protected against the elevation in blood pressure during exposure to CIH. To determine if the blunted blood pressure response to CIH in females was associated with diminished sodium and water retention, we evaluated sodium and water homeostasis in female rats exposed to CIH. Female Sprague‐Dawley rats (n=9) were placed in metabolic cages in enclosed chambers and exposed to 7 days of room air (control), 7 days of CIH, and 7 days of room air (recovery). CIH is defined as continuous cycles of 3 minutes of room air (21% O 2 ) and 3 minutes of 10% O 2 for 8 hours (Hypoxia: 8 am to 4 pm). During the remaining 16 hours (No‐Hypoxia: 4 pm to 8 am) the animals breathed room air. Water intake, urine volume, sodium intake, and urine sodium concentration were measured during the Hypoxia and No‐Hypoxia periods of the day for the 21 days of the experiment. We observed no significant differences in sodium and water balances between control, CIH, and recovery periods. These results are in contrast to our previous observations of sodium and water retention in males exposed to CIH during the No‐Hypoxia period of the day. We conclude that females maintain sodium and water balance during CIH which may contribute to the associated blunted elevation in blood pressure.