The research proposed is designed to address the unifying hypothesis that endothelial-derived prostacyclin permits newborn cerebral microvascular smooth muscle to dilate in response to specific stimuli. To test this hypothesis, four specific aims will be pursued using newborn pigs: l) Determine, in vivo, the ability of prostacyclin to restore cerebral vasodilator responses inhibited by indomethacin and by endothelial injury. 2) Examine the relationship between the ability of prostacyclin to restore vasodilation and changes in cyclic nucleotide metabolism. 3) Characterize, in vivo, the relationship between cerebral microvascular endothelial cell prostacyclin synthesis and smooth muscle cAMP in response to increased CO2. 4) Investigate the mechanisms by which prostacyclin modifies cerebral microvascular smooth muscle responses to hypercapnia. To accomplish these aims, techniques allowing investigation of intact cerebral microcirculation and primary culture of cells from newborn pig brain will be employed. Such research will be unique by studying the intact newborn cerebral circulation, isolated components that contribute to control of that circulation, and cocultures of these components to investigate mechanisms of communication. Cranial windows allow observation of cerebral microcirculation, collection of cortical periarachnoid fluid, selective endothelial damage, in vivo, and topical application of treatments and putative permissive agonists and inhibitors. Piglet cerebral microvascular endothelial and smooth muscle cells in primary culture will be used to study the effects of endothelial prostacyclin on smooth muscle cAMP responses to CO2. Effects of stable prostacyclin analogs on cerebral microvascular smooth muscle cAMP responses to CO2 will be evaluated. cAMP produced in response to CO2 by endothelial and vascular smooth muscle cells grown in isolation and together will be measured. To examine the relative contributions of intracellular and extracellular pH to the smooth muscle response to hypercapnia, using piglet cerebral microvascular smooth muscle cells in culture, we will measure cAMP production in response to decreases of pH-i with constant pH-e and in response to reduction of pH-e while maintaining pH-i. Selected potential cellular messenger pathways for involvement in the permissive role of prostacyclin in the microvascular smooth muscle response to hypercapnia will be evaluated. The effect of CO2 on iloprost receptor binding, the contributions of protein phosphorylation to the permissive role of prostacyclin and the kinases and substrates involved will be studied. Since disorders of cerebral circulation are major causes of morbidity and mortality in neonates and can result in lifelong disabilities in survivors better understanding of factors controlling newborn cerebral hemodynamics is badly needed.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
2R01HL042851-05
Application #
2220719
Study Section
Human Embryology and Development Subcommittee 1 (HED)
Project Start
1991-08-16
Project End
2000-07-31
Budget Start
1995-08-01
Budget End
1996-07-31
Support Year
5
Fiscal Year
1995
Total Cost
Indirect Cost
Name
University of Tennessee Health Science Center
Department
Physiology
Type
Schools of Medicine
DUNS #
941884009
City
Memphis
State
TN
Country
United States
Zip Code
38163
Pourcyrous, Massroor; Chilakala, Sandeep; Elabiad, Mohamad T et al. (2018) Does prolonged severe hypercapnia interfere with normal cerebrovascular function in piglets? Pediatr Res 84:290-295
Liu, Jianxiong; Pourcyrous, Massroor; Fedinec, Alex L et al. (2017) Preventing harmful effects of epileptic seizures on cerebrovascular functions in newborn pigs: does sex matter? Pediatr Res 82:881-887
Harsono, Mimily; Pourcyrous, Massroor; Jolly, Elliott J et al. (2016) Selective head cooling during neonatal seizures prevents postictal cerebral vascular dysfunction without reducing epileptiform activity. Am J Physiol Heart Circ Physiol 311:H1202-H1213
Chang, Jennifer; Fedinec, Alexander L; Kuntamallappanavar, Guruprasad et al. (2016) Endothelial Nitric Oxide Mediates Caffeine Antagonism of Alcohol-Induced Cerebral Artery Constriction. J Pharmacol Exp Ther 356:106-15
Liu, Jianxiong; Fedinec, Alexander L; Leffler, Charles W et al. (2015) Enteral supplements of a carbon monoxide donor CORM-A1 protect against cerebrovascular dysfunction caused by neonatal seizures. J Cereb Blood Flow Metab 35:193-9
Pourcyrous, Massroor; Basuroy, Shyamali; Tcheranova, Dilyara et al. (2015) Brain-derived circulating endothelial cells in peripheral blood of newborn infants with seizures: a potential biomarker for cerebrovascular injury. Physiol Rep 3:
Nnorom, Chukwuma C; Davis, Corinne; Fedinec, Alexander L et al. (2014) Contributions of KATP and KCa channels to cerebral arteriolar dilation to hypercapnia in neonatal brain. Physiol Rep 2:
Bukiya, Anna; Dopico, Alejandro M; Leffler, Charles W et al. (2014) Dietary cholesterol protects against alcohol-induced cerebral artery constriction. Alcohol Clin Exp Res 38:1216-26
Basuroy, Shyamali; Leffler, Charles W; Parfenova, Helena (2013) CORM-A1 prevents blood-brain barrier dysfunction caused by ionotropic glutamate receptor-mediated endothelial oxidative stress and apoptosis. Am J Physiol Cell Physiol 304:C1105-15
Bukiya, Anna N; McMillan, Jacob E; Fedinec, Alexander L et al. (2013) Cerebrovascular dilation via selective targeting of the cholane steroid-recognition site in the BK channel ?1-subunit by a novel nonsteroidal agent. Mol Pharmacol 83:1030-44

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