General Pharmacology: The Vascular System
General papersExperimental hyperlipidemia prevents the protective effect of ischemic preconditioning on the contractility and responsiveness to phenylephrine of rat-isolated stunned papillary muscle
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Animals
Albino-Wistar rats of either gender, weighing 180–220 g were used. The isolated cardiac tissues were divided in four experimental groups: (1) muscles obtained from standard diet-fed rats (SD), (2) SD preparations underwent PC, (3) muscles obtained from hyperlipidemic diet-fed rats (HLD), and (4) HLD muscles underwent PC. The rats were housed in wire mesh bottom cages (one animal per cage) and kept in standard laboratory conditions (12 h light-dark cycle, 21–24°C, humidity 50–55%), with food
Effects of diet on the cholesterol and triglyceride serum levels
Total serum cholesterol and serum triglyceride concentrations were determined in 8 animals from hyperlipidemic diet-fed rats (HLD) and 8 animals from standard diet-fed rats (SD), after 30 days of diet, using commercial biochemical tests. It has been found a significant increase either in level of cholesterol (63.4 ± 3 mg/dl in SD group vs. 82.3 ± 6 mg/dl, p < 0.05) or triglyceride (62.6 ± 13 mg/dl vs. 120.5 ± 22.5 mg/dl, p < 0.01).
Effects of the diet on the heart muscle and coronary vessels morphology
Using HE-staining 200X, we have compared the structure of
Discussion
The major finding of this study is that papillary muscles obtained from HLD rats have shown a lack of ability to be preconditioned by the PC procedure which rendered the cardiac tissue obtained from SD rats to be more resistent to ischemia regarding contractility and responsiveness to phenylephrine. It is not clear what the reason for this is. Apparent differences in time course of contractility and responsiveness to phenylephrine between papillary muscles obtained from SD- and HLD-fed rats
Acknowledgements
Authors are grateful to Dr. Ewa Wróblewska from the Department of Clinical Biochemistry, Medical University of Gdańsk, for determination of the serum cholesterol and triglyceride levels in rats. This study was partially supported by grant W-928 to I.K.
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