Baroreceptor and chemoreceptor reflexes are actively involved in the control of fetal blood pressure and in the maintenance of blood flow to the placenta and to the metabolizing tissues. The present project is an investigation into the mechanism of the baro- and chemoreflexes. In the first two funding periods of this project, we discovered and explored the interaction between changes in fetal blood pressure and prostaglandin generation in the fetal brain. In the immediate past funding period, we found that prostaglandin synthase -1 (PGHS-1) activity in the fetal brain augments reflex activity and that PGHS-2 activity decreases reflex activity. We found that denervation of the arterial baroreceptor/chemoreceptors does not, by itself, alter the expression of these enzymes in the fetal brain;PGHS-2 expression (and likely subsequent activity) is upregulated by transient hypotension. We have also initiated the use of a cell culture model to make significant progress in understanding the molecular mechanism of the PGHS-2 response to oxygen and glucose deprivation. These discoveries suggest that the immediate response to hypotension in the fetus is dependent upon PGHS-1 acitivty, but that the more delayed increase in PGHS-2 may bias subsequent responses and predispose the fetus to hypoxic damage. These findings have led us to propose the following specific aims, to propose to answer the following questions: 1) is there an association of glutaminergic pathways and prostanoids in the mediation of the reflex respones to cerebral hypoperfusion? 2) Is the ability of the fetus to maintain blood pressure and blood gases during hypovolemia impaired by blockade of prostaglandin biosynthesis or NMDA receptors? 3) What is the molecular and cellular basis of the upregulation of PGHS-2 in response to hypotension? In the proposed 5-year continuation of this project, the answers to these questions will significantly enhance our understanding of the mechanism by which prostanoids act within the brain to alter cardiovascular function. We will answer all of these questions using in vivo as well as cellular and molecular techniques. The results will build on our previous discoveries to significantly improve our understanding of the mechanism of the fetal stress response during hypotension. The results will identify the processes within the reflex pathway that can be manipulated pharmacologically and therefore enhance fetal survival during hypotensive stress.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
5R01HD033053-13
Application #
7741714
Study Section
Special Emphasis Panel (ZRG1-EMNR-G (05))
Program Officer
Ilekis, John V
Project Start
1996-05-03
Project End
2011-11-30
Budget Start
2009-12-01
Budget End
2010-11-30
Support Year
13
Fiscal Year
2010
Total Cost
$258,810
Indirect Cost
Name
University of Florida
Department
Physiology
Type
Schools of Medicine
DUNS #
969663814
City
Gainesville
State
FL
Country
United States
Zip Code
32611
Zarate, Miguel A; Rodriguez, Michelle D; Chang, Eileen I et al. (2017) Post-hypoxia Invasion of the fetal brain by multidrug resistant Staphylococcus. Sci Rep 7:6458
Chang, Eileen I; Zárate, Miguel A; Rabaglino, Maria B et al. (2016) Ketamine decreases inflammatory and immune pathways after transient hypoxia in late gestation fetal cerebral cortex. Physiol Rep 4:
Wood, Charles E; Chang, Eileen I; Richards, Elaine M et al. (2016) Transcriptomics Modeling of the Late-Gestation Fetal Pituitary Response to Transient Hypoxia. PLoS One 11:e0148465
Chang, Eileen I; Zárate, Miguel A; Rabaglino, Maria B et al. (2016) Ketamine suppresses hypoxia-induced inflammatory responses in the late-gestation ovine fetal kidney cortex. J Physiol 594:1295-310
Chang, Eileen I; Wood, Charles E (2015) Ketamine Attenuates the ACTH Response to Hypoxia in Late-Gestation Ovine Fetus. Neonatology 107:249-55
Rabaglino, Maria B; Keller-Wood, Maureen; Wood, Charles E (2014) Transcriptomics of the late gestation ovine fetal brain: modeling the co-expression of immune marker genes. BMC Genomics 15:1001
Wood, Charles E; Rabaglino, Maria Belen; Richards, Elaine et al. (2014) Transcriptomics of the fetal hypothalamic response to brachiocephalic occlusion and estradiol treatment. Physiol Genomics 46:523-32
Wood, Charles E; Rabaglino, Maria Belen; Chang, Eileen I et al. (2013) Genomics of the fetal hypothalamic cellular response to transient hypoxia: endocrine, immune, and metabolic responses. Physiol Genomics 45:521-7
Wood, Charles E; Keller-Wood, Maureen (2011) Influence of estradiol and fetal stress on luteinizing hormone, follicle-stimulating hormone, and prolactin in late-gestation fetal sheep. Neonatology 100:155-61
Fraites, Melanie J P; Wood, Charles E (2011) Chemoreflex activity increases prostaglandin endoperoxide synthase mRNA expression in the late-gestation fetal sheep brain. Reprod Sci 18:824-31

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