替米沙坦衍生物Tek-1的体内外药理学作用研究

Pharmacological research of a telmisartan derivative Tek-1 in vivo and in vitro

目的研究全新结构的替米沙坦衍生物Tek-1是否具有阻断血管紧张素Ⅱ(ANGⅡ)Ⅰ型受体(angiotensinⅡtypeⅠreceptor,AT1)和激活过氧化物酶体增殖物激活受体γ(peroxisome proliferator-activated receptor-γ,PPARγ)的双重特性,并在自发性高血压大鼠(spontaneously hypertensiverat Rat,SHR)上观察Tek-1对血压的影响。方法采用[3H]-ANGⅡ放射性受体配体结合实验,研究Tek-1与大鼠原代血管平滑肌细胞的AT1受体的亲和力;采用荧光素酶报告基因检测方法,研究Tek-1对PPARγ的激动活性;采用细胞内钙流动检测方法,研究Tek-1对ANGⅡ激动AT1受体的拮抗效应;采用SHR模型,评价Tek-1的体内降压效应。结果 Tek-1和替米沙坦对AT1受体均具有较高亲和力,Ki值分别为2.3×10^(-10)和1.1×10^(-9)mol/L;0.1~10μmol/L Tek-1和替米沙坦均能浓度依赖地激活PPARγ,10μmol/L Tek-1对荧光素酶的诱导倍数高于替米沙坦,分别为1.56±0.08和1.39±0.14倍;0.0128~1μmol/L Tek-1能浓度依赖地拮抗ANGⅡ诱导的细胞内钙流增加,IC50值为1.02±0.1 nmol/L;替米沙坦低、高剂量组(5和10 mg/kg,1次/d)和Tek-1低、中、高剂量组(1、5和10 mg/kg,1次/d)连续1周灌胃给药。与给药前基础血压相比,替米沙坦低、高剂量组显著降低SHR的收缩压(P<0.01)和舒张压(P<0.05);Tek-1低、中、高剂量组显著降低SHR的收缩压(P<0.05),Tek-1高剂量组能显著降低SHR的舒张压(P<0.05)。结论 Tek-1具有拮抗AT1受体和部分激活PPARγ受体的双重作用,能显著降低SHR的收缩压和舒张压。

Objective To investigate the dual pharmacology characteristics of a new structural telmisartan derivative Tek-1based on angiotensin Ⅱ（ANGⅡ）receptor Ⅰ（AT1）and peroxisome proliferator-activated receptor-γ（PPARγ）and the influence of Tek- 1 on blood pressure in spontaneously hypertensive rats（SHR）. Methods The AT1 receptor affinity of Tek- 1 was explored through radioligand binding assay on rat primary vascular smooth muscle cells;the PPARγ agonistic activity of Tek-1 was explored using PPARγ-responsive element-luciferase report assay;the antagonistic effect of Tek-1 on AT1 receptor activation induced by ANGⅡwas explored using intracellular calcium mobilization detection assay;the effect of Tek-1 on the regulation of systolic blood pressure（SBP）was evaluated in SHR in vivo. Results Tek-1 and telmisartan had high affinity to AT1 receptor,their Kivalues for AT1 receptor were 1.1×10^（-9） and 2.3×10^（-10）mol/L,respectively. Tek-1 and telmisartan could activate PPARγ ranging from 0.1 to 10 μmol/L in a concentration-dependent manner. The relative lucifarase activity induced by Tek-1 and telmisartan were 1.56±0.08 and 1.39±0.14 fold at10 μmol/L. Compared with solvent group,the effect of AT1 agonist ANGⅡ were inhibited by Tek-1 in a concentration-dependent manner with IC50 value of 1.02±0.1 nmol/L ranging from 0.0128 to 1 μmol/L. SHR were randomly administered telmisartan（5 or 10 mg/kg）and Tek-1（1 mg/kg,5 mg/kg or 10 mg/kg）orally each day for one week every day. After 1-week treatment,compared with the baseline SBP and DBP in the pretreatment of SHR,telmisartan in the dose of 5 and 10 mg/kg both showed significantly decreased SBP（P〈0.01）and DBP（P〈0.05）. Tek-1 in the dose of 1,5 and 10 mg/kg also significantly decreased SBP（P〈0.05）;however,only the high dose of 10 mg/kg Tek-1 showed a significant decrease in DBP（P〈0.05）. Conclusion Tek-1 Behaveds as an ATⅠ blocker with partial PPARγ agonist activity in vitro and attenuates the blood pressure in SHR in vivo.