Paper Information

Title: 

A COMPARATIVE STUDY ON THE CARDIOVASCULAR EFFECTS OF HIGH CHOLESTEROL FEEDING ON THE MALE AND FEMALE RATS

Type: POSTER
Author(s): FAROKHFAL KH.*,FATEHI HASANABAD Z.,GHOLAMNEZHAD Z.
 
 *BIRJAND UNIVERSITY OF MEDICAL SCIENCE
 
Name of Seminar: IRANIAN CONGRESS OF PHYSIOLOGY AND PHARMACOLOGY
Type of Seminar:  CONGRESS
Sponsor:  PHYSIOLOGY AND PHARMACOLOGY SOCIETY, MASHHAD UNIVERSITY OF MEDICAL SCIENCE
Date:  2007Volume 18
 
 
Abstract: 

The present study was designed to compare the effects of hypercholesterolemia on the cardiovascular responses to vasoconstrictor and vasodilators in male and female rats (both in vivo and in vitro on isolated aortic rings). The possible involvement of nitric oxide and protein tyrosine kinase on vascular changes caused by hypercholesterolemia, were also investigated. Hypercholesterolemia (HC) was induced by feeding male and female rats with a synthetic diet containing the regular diet with 2% cholesterol for 24 weeks, control rats received a normal diet for the same period. After 24 weeks, arterial blood pressure, total cholesterol, triglyceride, low density lipoprotein and high density lipoprotein cholesterol (LDL and HDL) were measured. In male and female rats, high cholesterol diet caused a significant increase in arterial blood pressure and total cholesterol, but a non-significant increase in triglyceride and LDL cholesterol level (compared to the controls). In anesthetized hypercholesterolemic male but not female rats, responses to acetylcholine were significatly reduced. However, in vitro responses to acetylcholine were significantly reduced in aortic rings isolated either from hypercholesterolemic male or female rats. Administration of aminoguanidine, an inducible nitric oxide synthase inhibitor, to either male and female rats (100 mg kg-1, ip., 2h prior to anesthesia) or tissue (10-5 M, incubated for 20 min) partially restored these impaired responses. Pre-treatment of tissue removed from HC male but not female rats with genistein, a tyrosine kinase inhibitor (10-5 M, for 20 min), also improved the responses to acetylcholine. These results suggest that vascular changes induced by HC in male rats are more pronounced than female rats, and inhibition of either inducible nitric oxide synthase or tyrosine kinase pathway could partially restored these changes.

 
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