Increased contractile responses to 5-hydroxytryptamine and Angiotensin II in high fat diet fed rat thoracic aortaReportar como inadecuado

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Lipids in Health and Disease

, 3:19

First Online: 02 August 2004Received: 23 June 2004Accepted: 02 August 2004


BackgroundFeeding normal rats with high dietary levels of saturated fat leads to pathological conditions, which are quite similar to syndrome X in humans. These conditions such as hypertriglyceridemia, hypercholesterolemia, obesity, and hyperglycemia might induce hypertension through various mechanisms. Metabolic syndrome and the resulting NIDDM represent a major clinical challenge because implementation of treatment strategies is difficult. Vascular abnormalities probably contribute to the etiology of many diabetic complications including nephropathy, neuropathy, retinopathy, and cardiomyopathy. It has been shown that in Streptozotocin induced diabetic animals there is an increase in maximal responses to 5-Hydroxytryptamine and Angiotensin II. The purpose of this study was to evaluate High fat diet fed rats for the development of hypertriglyceridemia, hypercholesterolemia, hyperinsulinemia and hyperglycemia and to assess their vascular responses to 5-Hydroxytryptamine and Angiotensin II.

MethodsMale Sprague Dawley rats were used for this study and were divided into two equal groups. One of the groups was fed with normal pellet diet and they served as the control group, whereas the other group was on a high fat diet for 4 weeks. Body weight, plasma triglycerides, plasma cholesterol, and plasma glucose were measured every week. Intraperitoneal glucose tolerance test was performed after 4 weeks of feeding. At the end of fourth week of high fat diet feeding, thoracic aortae were removed, and cut into helical strips for vascular reactivity studies. Dose-response curves of 5-Hydroxytryptamine and Angiotensin II were obtained.

ResultsThere was no significant difference in pD2, with 5-Hydroxytryptamine and Angiotensin II in both groups but Emax was increased.

ConclusionsThese results suggest that hypertension in high fat diet rats is associated with increased in vitro vascular reactivity to 5-HT and Ang II.

List of abbreviationsHFDHigh fat diet

NPDNormal pellet diet

NIDDMNon insulin dependent diabetes mellitus



Ang IIAngiotensin II

KHSKrebs-Henseleit solution

GOD-PODGlucose oxidase-peroxidase

AUCarea under the curve

EmaxMaximal response

EC50Concentration required producing 50% of maximal response

pD2-log EC50

Electronic supplementary materialThe online version of this article doi:10.1186-1476-511X-3-19 contains supplementary material, which is available to authorized users.

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Autor: Srinivas Ghatta - Poduri Ramarao


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