卒中易感型自发性高血压大鼠血管平滑肌收缩装置对Ca2＋敏感性变化的研究

ChangesinCalciumSensitivetyoftheContractileApparatusofVascularSmoothMusclesfromStroke-proneSpontaneouslyHypertensiveRatsandtheRoleofProteinKinaseC

目的比较卒中易感型自发性高血压大鼠（ＳＨＲｓｐ）与常压（Ｗｉｓｔａｒ）大鼠基底动脉（ＢＡ）和尾动脉（ＣＡ）平滑肌收缩装置对Ｃａ２＋敏感性（以ｐＣａ５０表示）的差异。方法采用血管平滑肌细胞（ＶＳＭＣ）膜化学高通透技术并结合细胞钙钳制技术，使上述血管肌条（环）平滑肌细胞膜具有高通透性，并使胞内Ｃａ２＋固定于一定水平，然后制作神经鞘氨醇（ｓｐｈｉｎｇｏｓｉｎｅ）预温浴后的肌条（环）ｐＣａ－张力曲线，比较ＳＨＲｓｐ和Ｗｉｓｔａｒ大鼠ＢＡ和ＣＡ平滑肌在不同处理时的ｐＣａ５０值。结果不论ＳＨＲｓｐ或Ｗｉｓ－ｔａｒ大鼠，ＢＡ平滑肌收缩装置对Ｃａ２＋的敏感性均高于ＣＡ（Ｐ＜０．００５）。ＳＨＰｓｐ的ＢＡ和ＣＡ平滑肌收缩装置对Ｃａ２＋的敏感性均高于Ｗｉｓｔａｒ大鼠的相应血管（Ｐ＜０．００５）。蛋白激酶Ｃ（ＰＫＣ）抑制剂Ｓｐｈｉｎｇｏｓｉｎｅ可使ＳＨＲｓｐＣＡ平滑肌ｐＣａ－张力曲线右移，但不能使ＳＨＲｓｐＣＡ平滑肌ｐＣａ－张力曲线右移，甚至轻微左移。结论ＳＨＲｓｐＢＡ和ＣＡ平滑肌收缩装置对Ｃａ２＋的敏感性均高于Ｗｉｓｔａｒ大鼠。

AimTocompareofthediferencesinCa2+sensitivityofthecontractileapparatusofsmoothmusclesandtheroleofproteinkinaseC(PKC)be-tweenstroke-pronespontaneouslyhypertensiverats(SHRsp)andnormotensiveWistarrats.MethodThepermeabilizedandcalciumclampedsmoothmus-clestripsofbasilarandcaudalarteriesfromSHRspandWistarratswereused.ResultsTheCa2+sensitivitywashigherinbasilararteriesthanthatincau-dalarteriesinbothSHRspandWistarrats.TheCa2+sensitivityofbasilarandcaudalarteriesfromSHRspwerehigherthanthatfromWistarrats.Sphingosine,thePKCinhibitor,couldshiftthepCa-tensioncurveofcaudalarterystripsrightward,butcouldnotshiftthepCa-tensioncurveofbasilararterystripsright-ward.ConclusionTheCa2+sesitivityofthecon-tractileapparatusofbasilarandcaudalarteriesfromSHRspwasincreasedandtheroleofPKCinthischangeofCa2+sensitivitywasheterogeneousbetweenbasilarandperipheralarterialsmoothmuscles.