自发性高血压大鼠血管α_1肾上腺素受体亚型的改变  

CHANGES OF SUBTYPES OF α_1-ADRENOCEPTOR IN BLOOD VESSELS OF SPONTANEOUSLY HYPERTENSIVE RATS

作　　者：韩启德[1] 李金玲[1] 陈咏梅[1] 

机构地区：[1]北京医科大学第三医院心血管研究室,北京100083

出　　处：《生理学报》1992年第3期229-236,共8页Acta Physiologica Sinica

基　　金：国家自然科学基金

摘　　要：本工作在离体与整体条件下比较易卒中型自发性高血压(SHRSP)大鼠与WKY大鼠血管中α_1受体的两种亚型。在离体灌流的主动脉、肾动脉与肠系膜动脉,50μmol/L氯甲基可乐定(CEC)预温育30min可使α_1受体激动时引起的最大收缩张力在SHRSP与WKY大鼠分别降为对照时的31.4±8.3％与35.2±2.9％,68.4±8.2％与80.1±7.3％,68.4±6.3％与55.4±7.0％,两者间均无显著性差别。但10μmol/L硝苯吡啶对α_1受体收缩效应的阻断作用则在SHRSP大鼠大大超过WKY大鼠,最大收缩张力分别降为对照时的3.1±1.5％与56.5±4.8％(P<0.01),9.0±4.1％与23.6±3.5％(P<0.05),5.9±2.5％与28.0±0.8％(P<0.01)。整体动物实验也显示硝苯吡啶的降血压作用及对苯肾上腺素升血压效应的阻断作用在SHRSP大鼠都较WKY大鼠显著增强。离体主动脉a_1受体激动时的快速相与持续相收缩均主要由α_(1B)亚型激动引起,硝苯吡啶对快速相收缩的阻断作用在SHRSP与WKY大鼠无显著性差别,但对持续相收缩的阻断作用则在SHRSP大鼠显著强于WKY大鼠。上述结果提示SHRSP大鼠血管α_1受体两种亚型的分布没有显著改变,但α_(1B)受体激动时继发性细胞外Ca^(2+)进入的途径由非双氢吡啶敏感性钙通道转变为双氢吡啶敏感性钙通道。The two subtypes of α_1-adrenoceptors in blood vessels were compared betweenstroke prone spontaneously hypertensive rats (SHRSP) and WKY rats in vitro andin vivo. Pretreatment with 50 μmol/L chlorethylclonidine (CEC) for 30mindecreased the maximal contractions induced by norepinephrine (NE)to 31.4±8.3% and 35.2±2.9% (aortae); 68.4±8.2% and 80.1±7.2% (renal arteries);68.4±6.3% and 5.4±7.0% (mesenteric arteries) of the controls in the SHRSPand the WKY rats, respectively. All the differences between the SHRSP andWKY rats were not statistically significant. In contrast, the blocking effects ofnifedipine were much stronger in the SHRSP rats than those in the WKY rats. Inthe presence of 10 μmol/L nifedipine the maximal contractions induced by NEwere decreased to 3.1±1.5% and 56.5±4.8% (P<0.01, aortae); 9.0±4.1%and 23.6±3.5% (P<0.05, renal arteries); 5.9±2.5% and 28.0±0.8% (P<0.01,mesenteric arteries) of the controls in the SHRSP and the WKY rats, respectively.The experiment in vivo also showed that the effects of nifedipine on decreasing basalblood pressure and on antagonizing phenylephrine were increased in the SHRSPrats, as compared to the WKY rats. Analyses of two components of the contrac-tions induced by 10 μmol/L NE in aortae demonstrated that both phasic andtonic contractions were mainly caused by activations of the α_(1B) subtype. Therewere no significant differences of blocking effects of nifedipine on the phasic con-tractions between the SHRSP and WKY rats. But the blocking effects on thetonic contractions were much stronger in the SHRSP rats than those in the WKYrats. The results suggest that in the SHRSP rats the distribution of the two sub-types of α_1-adrenoceptors, i.e. the ratio of α_(1A)VS α_(1B) is not changed, but the secon-dary entry of Ca^(2+) during activation of α_(1B)-adrenoceptors may be mediated by nife-dipine sensitive calcium channels rather than by nifedipine insensitive ones asshownin the WKY rats.

关 键 词：受体亚型 血管 高血压 肾上腺素 

分 类 号：R544.102[医药卫生—心血管疾病]