Endogenous brain erythropoietin is a potent sex-specific respiratory stimulant in adult and newborn mice.

TitleEndogenous brain erythropoietin is a potent sex-specific respiratory stimulant in adult and newborn mice.
Publication TypeJournal Article
Year of Publication2015
AuteursBallot, O, Joseph, V, Soliz, J
JournalJ Appl Physiol (1985)
Volume118
Issue11
Pagination1386-95
Date Published2015 Jun 01
ISSN1522-1601
KeywordsAdaptation, Physiological, Age Factors, Animals, Animals, Newborn, Brain, Carbon Dioxide, Disease Models, Animal, Erythropoietin, Female, Hypoxia, Injections, Intraventricular, Male, Mice, Inbred C57BL, Oxygen Consumption, Pulmonary Ventilation, Receptors, Erythropoietin, Respiration, Respiratory Rate, Sex Factors, Signal Transduction, Tidal Volume, Time Factors
Abstract

We tested the hypothesis that endogenous brain Epo is a respiratory stimulant. Adult (3 mo) and newborn (10 days) male and female mice received an intracisternal (cisterna magna) injection of soluble Epo receptor (sEpoR; competes with EpoR to bind Epo; 50 μg/ml) or vehicle (0.1% BSA in PBS). Twenty-four hours after injection, we used whole body plethysmography to record minute ventilation (V̇e) tidal volume (VT), respiratory frequency (fR), O2 consumption (V̇o2), and CO2 production (V̇co2) under normoxia and progressive exposure to hypoxia (12-10-6% O2; 10 min each). In adult male and female mice sEpoR decreased normoxic V̇e (-25%), due to a decrease of VT in males and fR in females. Moreover, sEpoR injection decreased the ventilatory response to 12% O2, assessed as V̇e/V̇o2 or V̇e/V̇co2, in male but not in female mice. In newborn male and female mice sEpoR decreased V̇e (-37% in males, -59% in females) and VT (-38% in males, -47% in females) in normoxia and fR in females. During hypoxia, sEpoR decreased V̇e/V̇o2 and V̇e/V̇co2 in mice of both sexes. Upon extreme hypoxia (6% O2), the newborn mice treated with sEpoR showed respiratory depression, signs of asphyxia (gasping) and a high mortality rate in males and females. We concluded that endogenous brain Epo is a potent respiratory stimulant under normoxia and hypoxia in adult and newborn mice. Because sex-specific effects are different in newborn male and female, sex steroids secreted at different ages mice appear to modulate the effects of Epo on respiratory regulation in normoxia and in response to hypoxia.

DOI10.1152/japplphysiol.00143.2015
Alternate JournalJ. Appl. Physiol.
PubMed ID25792712
Grant ListMOP 130258 / / Canadian Institutes of Health Research / Canada