The effects of hypertension on neurovascular unit function and structure

Hdl Handle:
http://hdl.handle.net/10675.2/621661
Title:
The effects of hypertension on neurovascular unit function and structure
Authors:
Iddings, Jennifer Ann
Abstract:
Functional hyperemia is the regional increase in cerebral blood flow upon increases in neuronal activity which ensures that the metabolic demands of the neurons are met. Hypertension is known to impair the hyperemic response; however, the neurovascular coupling mechanisms by which this cerebrovascular dysfunction occurs have yet to be fully elucidated. The goal of this dissertation project was to test the central hypothesis that hypertension-induced impairments in functional hyperemia are mediated by a specific disruption of communication within the neurovascular unit at the parenchymal arteriole level of the cerebrovascular tree. To test our hypothesis, we measured parenchymal arteriole reactivity, vascular smooth muscle cell Ca2+ dynamics, parenchymal arteriole remodeling and cerebral vascular density in cortical brain slices from normotensive (WKY) and hypertensive (SHR) rats. We found that vasoconstriction in response to the thromboxane A2 receptor agonist U46619 and basal vascular smooth muscle cell Ca2+ oscillation frequency were increased in parenchymal arterioles from SHR. In perfused and pressurized parenchymal arterioles, myogenic tone was increased in SHR. While K+-induced parenchymal arteriole dilations were similar in WKY and SHR, metabotropic glutamate receptor activation-induced parenchymal arteriole dilations were enhanced in SHR. Further, neuronal stimulation-evoked parenchymal arteriole dilations were similar in SHR and WKY. Parenchymal arteriole wall to lumen ratio and wall thickness were increased in SHR. Vascular density was also increased in deeper cortical layers in SHR. Our data indicate that although SHR parenchymal arterioles display vascular remodeling, neurovascular coupling is not impaired in SHR, at least at the parenchymal arteriole level.
Affiliation:
Department of Physiology
Issue Date:
2015
URI:
http://hdl.handle.net/10675.2/621661
Additional Links:
http://ezproxy.augusta.edu/login?url=https://search.proquest.com/docview/1681645132?accountid=12365
Type:
Dissertation
Appears in Collections:
Theses and Dissertations; Department of Physiology Theses and Dissertations

Full metadata record

DC FieldValue Language
dc.contributor.authorIddings, Jennifer Annen
dc.date.accessioned2017-12-29T15:55:59Z-
dc.date.available2017-12-29T15:55:59Z-
dc.date.issued2015-
dc.identifier.urihttp://hdl.handle.net/10675.2/621661-
dc.description.abstractFunctional hyperemia is the regional increase in cerebral blood flow upon increases in neuronal activity which ensures that the metabolic demands of the neurons are met. Hypertension is known to impair the hyperemic response; however, the neurovascular coupling mechanisms by which this cerebrovascular dysfunction occurs have yet to be fully elucidated. The goal of this dissertation project was to test the central hypothesis that hypertension-induced impairments in functional hyperemia are mediated by a specific disruption of communication within the neurovascular unit at the parenchymal arteriole level of the cerebrovascular tree. To test our hypothesis, we measured parenchymal arteriole reactivity, vascular smooth muscle cell Ca2+ dynamics, parenchymal arteriole remodeling and cerebral vascular density in cortical brain slices from normotensive (WKY) and hypertensive (SHR) rats. We found that vasoconstriction in response to the thromboxane A2 receptor agonist U46619 and basal vascular smooth muscle cell Ca2+ oscillation frequency were increased in parenchymal arterioles from SHR. In perfused and pressurized parenchymal arterioles, myogenic tone was increased in SHR. While K+-induced parenchymal arteriole dilations were similar in WKY and SHR, metabotropic glutamate receptor activation-induced parenchymal arteriole dilations were enhanced in SHR. Further, neuronal stimulation-evoked parenchymal arteriole dilations were similar in SHR and WKY. Parenchymal arteriole wall to lumen ratio and wall thickness were increased in SHR. Vascular density was also increased in deeper cortical layers in SHR. Our data indicate that although SHR parenchymal arterioles display vascular remodeling, neurovascular coupling is not impaired in SHR, at least at the parenchymal arteriole level.en
dc.relation.urlhttp://ezproxy.augusta.edu/login?url=https://search.proquest.com/docview/1681645132?accountid=12365en
dc.rightsCopyright protected. Unauthorized reproduction or use beyond the exceptions granted by the Fair Use clause of U.S. Copyright law may violate federal law.en
dc.subjectBiological sciencesen
dc.subjectAstrocyteen
dc.subjectBrain Sliceen
dc.subjectFunctional Hyperemiaen
dc.subjectHypertensionen
dc.subjectNeurovascula Couplingen
dc.subjectParenchymal Arterioleen
dc.titleThe effects of hypertension on neurovascular unit function and structureen
dc.typeDissertationen
dc.contributor.departmentDepartment of Physiologyen
dc.description.advisorFlilosa, Jessica A.en
dc.description.committeeDhandapani, Krishnan; Ergul, Adviye; Kirov, Sergei; Seki, Tsugio; Yoon, Yisangen
dc.description.degreeDoctor of Philosophy (Ph.D.)en
dc.description.majorDoctor of Philosophy with a Major in Physiologyen
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