Adrenergic receptor blocking agents and the central hypertensive activity of angiotensin II

dc.contributor.advisorBuckley, Joseph P.
dc.contributor.committeeMemberOró, John F.
dc.contributor.committeeMemberClarke, David E.
dc.contributor.committeeMemberSpring, Thomas G.
dc.contributor.committeeMemberKimball, Aubrey P.
dc.creatorVollmer, Regis Robert
dc.date.accessioned2022-09-23T16:47:21Z
dc.date.available2022-09-23T16:47:21Z
dc.date.copyright1975
dc.date.issued1975
dc.description.abstractPressor responses to intraventricularly administered (IVT) angiotensin II (AII) were markedly potentiated by IVT phentolamine (50, 100 or 200 ug/min for 30 min), not altered by tolazoline (140 ug/min for 30 min) and significantly reduced by phenoxybenzamine (100 ug/min for 30 min). Phentolamine, IVT, also produced a centrally mediated dose-related decrease in blood pressure (BP) and heart rate (HR). Selective perfusion studies indicated that the primary site of action for the hypotension was located in the subarachnoid spaces and a secondary site was identified anterior to the midbrain adjacent to the ventricular spaces. The bradycardia was probably dependent upon an activation of central vagal nuclei and was absent in vagotomized animals. Reflexogenic bradycardia elicited by intravenous norepinephrine or AII was reduced. Similarly, reflex hypotension and bradycardia induced by carotid sinus nerve stimulation were diminished. Tolazoline, IVT, did not produce cardiovascular alterations. However, phenoxybenzamine, IVT, significantly increased BP and HR. d- or 1-propranolol (10 ug/min for 30 min), IVT, did not alter the central hypertensive activity of All. Both isomers significantly reduced BP to an equal extent suggesting that beta-blockade is not necessary for the hypotension. 1-Propranolol, IVT, produced greater reductions in HR which may have been related to the development of peripheral beta-blockade as evidenced by antagonism of intravenous isoproterenol responses.
dc.description.departmentBiology and Biochemistry, Department of
dc.format.digitalOriginreformatted digital
dc.format.mimetypeapplication/pdf
dc.identifier.other2782232
dc.identifier.urihttps://hdl.handle.net/10657/11862
dc.language.isoen
dc.rightsThis item is protected by copyright but is made available here under a claim of fair use (17 U.S.C. Section 107) for non-profit research and educational purposes. Users of this work assume the responsibility for determining copyright status prior to reusing, publishing, or reproducing this item for purposes other than what is allowed by fair use or other copyright exemptions. Any reuse of this item in excess of fair use or other copyright exemptions requires express permission of the copyright holder.
dc.titleAdrenergic receptor blocking agents and the central hypertensive activity of angiotensin II
dc.type.dcmiText
dc.type.genreThesis
dcterms.accessRightsThe full text of this item is not available at this time because it contains documents that are presumed to be under copyright and are accessible only to users who have an active CougarNet ID. This item will continue to be made available through interlibrary loan.
thesis.degree.collegeCollege of Natural Sciences and Mathematics
thesis.degree.departmentBiophysical Sciences, Department of
thesis.degree.disciplineBiophysical Sciences
thesis.degree.grantorUniversity of Houston
thesis.degree.levelDoctoral
thesis.degree.nameDoctor of Philosophy
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