The role played by angiotensin (1-7) in the regulation of renal haemodynamics and excretory function in anesthetized rats

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dc.check.date10000-01-01
dc.check.embargoformatE-thesis on CORA onlyen
dc.check.entireThesisEntire Thesis Restricted
dc.check.infoIndefiniteen
dc.check.opt-outYesen
dc.check.reasonThis thesis is due for publication or the author is actively seeking to publish this materialen
dc.contributor.advisorJohns, Edward J.en
dc.contributor.authorO'Neill, Julie
dc.contributor.funderIrish Research Council for Science Engineering and Technologyen
dc.date.accessioned2014-06-19T13:19:45Z
dc.date.issued2013
dc.date.submitted2013
dc.description.abstractInitial studies have demonstrated that intra- renal infusion of Ang (1-7) caused a diuresis and natriuresis that was proportional to the degree of activation of the Renin Angiotensin Aldosterone System (RAAS). This raised the question as why the magnitude of this diuresis and natriuresis was compromised in rats receiving a high sodium diet (suppressed RAAS) and enhanced in low sodium fed rats (activated RAAS)? Could the answer lie with changes in intra-renal AT1 or Mas receptor expression? Interestingly, the observed Ang (1-7) induced increases in sodium and water excretion in rats receiving either a low or normal sodium diet were and blocked in the presence of the AT 1 receptor antagonist (Losartan) in the presence of the, 'Mas' receptor antagonist (A-779). These data suggest that both AT1 and 'Mas' receptors need to be functional in order to fully mediate the renal responses to intra-renal Ang (1-7) infusion. Importantly, further experimentation also revealed that there is a proportional relationship between AT 1 receptor expression in the rat renal cortex and the magnitude of the excretory actions of intra renal Ang (1-7) infusion, which is only partially dependent on the level of 'Mas' receptor expression. These observations suggest that although Ang (1-7) induced increases in sodium and water excretion are mediated by the Mas receptor, the magnitude of these excretory responses appear to be dependent upon the level of AT 1 receptor expression and more specifically Ang II/ AT 1 receptor signalling. Thus in rats receiving a low sodium diet, Ang (1-7) acts via the Mas receptor to inhibit Ang II/ AT 1 receptor signalling. In rats receiving a high sodium diet the down regulated AT 1 receptor expression implies a reduction in Ang II/ AT 1 receptor signalling which renders the counter-regulatory effects of intra-renal Ang (1-7) infusion redundant.en
dc.description.statusNot peer revieweden
dc.description.versionAccepted Version
dc.format.mimetypeapplication/pdfen
dc.identifier.citationO'Neill, J. 2013. The role played by angiotensin (1-7) in the regulation of renal haemodynamics and excretory function in anesthetized rats. PhD Thesis, University College Cork.en
dc.identifier.urihttps://hdl.handle.net/10468/1581
dc.language.isoenen
dc.publisherUniversity College Corken
dc.rights© 2013, Julie O Neill.en
dc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/3.0/en
dc.subjectMas receptorsen
dc.subjectSodium and water excretionen
dc.subjectRenal interstitial infusionen
dc.subjectAT2en
dc.subjectAng (1-7) AT1en
dc.thesis.opt-outtrue
dc.titleThe role played by angiotensin (1-7) in the regulation of renal haemodynamics and excretory function in anesthetized ratsen
dc.typeDoctoral thesisen
dc.type.qualificationlevelDoctoralen
dc.type.qualificationnamePhD (Science)en
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