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Gestational stress delays maturation of the hypoxic ventilatory response: an in vivo and in vitro study
Author(s) -
Kinkead Richard,
Fournier Stéphanie,
Fournier Sébastien,
Voituron Nicolas,
Hilaire Gérard
Publication year - 2009
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.23.1_supplement.961.9
Subject(s) - hypoxia (environmental) , gestation , in vivo , respiratory system , biology , respiration , medicine , endocrinology , anesthesia , chemistry , anatomy , pregnancy , microbiology and biotechnology , genetics , organic chemistry , oxygen
Exposure to stress during gestation disrupts CNS development; however, its effects on the respiratory control system are unknown. We tested the hypothesis that exposing dams to a predator odor during gestation disrupts the maturation of the hypoxic ventilatory response (HVR) of newborn rats. From the 9 th to the 19 th day of pregnancy, females subjected to gestational stress (GS) were placed in a cage containing 35 μl of TMT, a component of fox odor for 20 min. For sham treatment, gestating females were exposed to a strong odor (butyric acid, 105 μl). Controls were undisturbed. Ventilatory activity was measured at post natal days 0, 2 and 4 using plethysmography ( in vivo ) and "en bloc" brainstem spinal cord preparations ( in vitro ). Measurements were performed under baseline conditions and hypoxia. In vivo : unlike controls, P4 male pups born to GS dams could not sustain a significant increase in breathing frequency through out the hypoxic period (12% O 2 , 20 min). This effect of GS was not observed in females. In vitro : at the end of hypoxia (7% O 2 , 20 min), preparations from GS pups showed a smaller phrenic burst frequency decrease than controls (‐58% vs ‐76%). No sexual dimorphism was observed in vitro . GS delays maturation of the hypoxic ventilatory response. Comparison of in vivo vs in vitro data suggests that GS affects peripheral chemoreceptor development and/or integration of afferent signal in the CNS. Supported by the CIHR.