| Objectives: Ischemic Heart Disease is already the most common cause of illness and death in western world and is increasing also in the developing world. Many preventive and treatment methods are being employed to deal with ischemic heart disease, such as operative treatment, pharmacotherapy, and so on. At present, the pharmacotherapy is the most important treatment method in the prophylaxis and treatment of myocardial ischemia. Due to more safety and less side effort, the traditional Chinese medicine has stirred the interest of researchers. Though there are a lot of reports that many traditional Chinese medicines have the anti-ischemia effect on myocardial ischemia, these researches are fairly scrappy and the overall and deep study reports are comparatively rare.Endothelin was isolated by Yanagisawa et al. from the pig arterial endothelinal cell culture. It is a peptide. Endothelin referred to as ET-1, ET-2 and ET-3. Normally, Endothelin is involved in the maintenance of baseline vascular smooth muscle tone. Endothelin contributes to basal coronary vasoconstriction tone and endothelial dysfunction. In some pathologic condition, the endothelin is highly secreted. The excess endothelin contributes to high coronary vasoconstriction, which leads to intensifying myocardial ischemia. Some studies have indicated that Tongqiaohuoxue decoction, a famous traditional Chinese medicine, has the clear protection effort on ischemic myocardium. So this research tries to take endothlin-1 as a breach to explicate the molecule mechanism of this protective effect.Methods and Results:1. The best model parameters of inducing myocardial ischemia by pituitrin were defined.1.1 The dosage effect of pituitrin on Endothelin-1 concentration in rat myocardium and plasma.Different doses of pituitrin were administered to rats to induce myocardial ischemia. The endothelin-1 concentration in rat myocardium and plasma was measured by radioimmunoassay. The results showed Endothelin-1 reached the maximum in myocardium when 15U/kg pituitrin was given. The pattern of Endothelin-1 in plasma was similar to that in myocardium. The results suggested that 15U/kg should be selected as the best dosage of pituitrin to induce myocardial ischemia.1.2 The time effect of pituitrin on Endothelin-1 concentration in rat myocardium and plasma.The best dosage of pituitrin, 15U/kg, was administered to rats and the changes of Endothelin-1 concentration in different time point in myocardium and plasma were determined respectively. The results showed that Endothelin-1 concentration reached the maximum after the pituitrin at 15U/kg was administered 1 hour. The results suggested that the best time effort point is 1 hour.2. Effects of Tongqiaohuoxue decoction on Endothelin-1 concentration in myocardium and plasma of myocardial ischemia rat.2.1 The dosage effect of Tongqiaohuoxue decoction on Endothelin-1 concentration in ischemia myocardium and plasma.The myocardium ischemia rats were administered with different dosage of Tongqiaohuoxue decoction. After 4 days, the Endothelin-1 concentration in myocardium and plasma was measured by radioimmunoassay. The results showed that at the dosage of 5g/kg, the Endothelin-1 concentration in myocardium decreased and when the dosage of Tongqiaohuoxue decoction was more than 5g/kg, the Endothelin-1 concentration inmyocardium fluctuated at the same value. At the dosage of lOg/kg, Endothelin-1 concentration in plasma decreased and increasing the dosage could not bring about reducing the Endothelin-1 concentration in plasma, the results suggested that the dosage of lOg/kg should be chose as the administration dosage.2.2 The time effect of tongqiaohuoxue decoction on Endothelin-1 concentration in myocardium and plasma of myocardial ischemia rat.Endothelin-1 concentration of ischemic myocardium and plasma was determined at 2,4,6,8 day after administering 10g/kg Tongqiaohuoxue decoction. The results showed that Endothelin-1 concentration in myocardium and plasma decreased at 4 day after administra...
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