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Age and sex differences in the hypercapnic ventilatory response in awake neonatal rats
Author(s) -
Wenninger Julie M,
Holley Heidi S,
Behan Mary
Publication year - 2010
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.24.1_supplement.613.1
Subject(s) - hypercapnia , apnea , ventilation (architecture) , tidal volume , medicine , sexual dimorphism , sudden infant death syndrome , respiratory system , endocrinology , chemoreceptor , plethysmograph , respiratory minute volume , obstructive sleep apnea , brainstem , physiology , receptor , mechanical engineering , pediatrics , engineering
Sex hormones exert powerful effects in the central nervous system during development. Little is known about sex differences in the development of chemoreceptors and their contribution to sexual dimorphism in respiratory diseases such as Sudden Infant Death Syndrome (SIDS) and Obstructive Sleep Apnea (OSA). Several chemo sensitive brainstem nuclei, including the caudal raphe, undergo structural and functional changes in early postnatal life. The purpose of this study was to determine whether there are sex differences in the ventilatory response to hypercapnia (F ICO2 = 7%) in rats from P10‐P15, and whether there are sex‐related changes in 5‐HT 1A receptor expression in the caudal raphe in these male and female rat pups. Awake neonatal rats were studied each day in a plethysmograph in normoxia and CO 2 . Arterial O 2 saturation was measured with a pulse oximeter. After the study, a blood sample was drawn for measurement of sex hormone levels. The animals were perfused and brainstems harvested for immunohistochemical evaluation. During CO 2 exposure we found sex differences in tidal volume (V T ) and minute ventilation (V E ) at postnatal days 11 and 15. There were also significant changes in breathing frequency, V T , and V E with age in each sex. These data suggest that there are sex differences in the hypercapnic ventilatory response in neonatal rats during a critical period of ventilatory development. Supported by NIH AG18760 and Parker B. Francis Foundation.