Age- and hypertension-induced changes in abnormal contractions in rat aorta

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dc.contributor.authorAbeywardena, M.
dc.contributor.authorJablonskis, L.
dc.contributor.authorHead, R.
dc.date.issued2002
dc.description.abstractThe current investigation explored the potential age-dependant modulation of abnormal spontaneous constrictions (thromboxane-like) in the spontaneously hypertensive rat (SHR) aorta, observed only after the inhibition of endogenous production of nitric oxide (NO). Aortic rings from SHR and Wistar-Kyoto (WKY) control rats of varying ages (4, 8, 12, and 18 months) were mounted in organ baths, and changes in tension were monitored. Inhibition of NO with Nω-nitro-L-arginine (NOLA) unmasked a slow contraction, which appeared to be age dependent (p < 0.05). This contraction was found in SHRs of all age groups and in older WKY rats. Denuding the endothelium in young SHRs did not influence the constriction, confirming a nonendothelial cell origin, while in the older groups this led to a 30–40% reduction in contraction. Comparable attenuation of the constrictor response was observed after incubation of endothelium intact rings with superoxide dismutase (100 U/ml) or 3-amino-1,2,4-triazole. Of the residual activity that was unaffected by free radical scavengers or de-endothelialization, 60–70% was sensitive to cyclooxygenase inhibition by indomethacin and/or ibuprofen. The thromboxane (TxA2) receptor antagonist SQ29548 induced a complete reversal of the abnormal constriction. In contrast, thromboxane synthetase inhibition had no effect, ruling out any involvement of TxA2 in mediating this abnormality. Collectively, these observations support the view that as compared with the normotensive setting, contraction induced by NO inhibition in the SHR develops prematurely and deteriorates more rapidly during the aging process. In aged rats, prostaglandin endoperoxide intermediates PGG2/H2 and endothelium-derived free radicals rather than TxA2 per se appear to contribute to the NOLA-dependent TxA2-like vasoconstriction.
dc.description.statementofresponsibilityMahinda Y. Abeywardena, Lina T. Jablonskis and Richard J. Head
dc.identifier.citationJournal of Cardiovascular Pharmacology, 2002; 40(6):930-937
dc.identifier.doi10.1097/00005344-200212000-00015
dc.identifier.issn0160-2446
dc.identifier.issn1533-4023
dc.identifier.orcidHead, R. [0000-0002-1196-0926]
dc.identifier.urihttp://hdl.handle.net/2440/14459
dc.language.isoen
dc.publisherLippincott Williams & Wilkins
dc.rights© 2002 Lippincott Williams & Wilkins, Inc.
dc.source.urihttp://journals.lww.com/cardiovascularpharm/Fulltext/2002/12000/Age__and_Hypertension_induced_Changes_in_Abnormal.15.aspx
dc.subjectCardiovascular disease
dc.subjectVertebrata
dc.subjectMammalia
dc.subjectRodentia
dc.subjectArachidonic acid derivatives
dc.subjectAge
dc.subjectInterindividual comparison
dc.subjectEndothelium
dc.subjectIn vitro
dc.subjectNitric oxide
dc.subjectCirculatory system
dc.subjectBlood vessel
dc.subjectRat
dc.subjectAnimal
dc.subjectSenescence
dc.subjectComplication
dc.subjectHypertension
dc.subjectAorta
dc.subjectSmooth muscle
dc.subjectMuscle contraction
dc.titleAge- and hypertension-induced changes in abnormal contractions in rat aorta
dc.typeJournal article
pubs.publication-statusPublished

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