血管紧张素Ⅱ对心肌成纤维细胞增殖及p21,p27表达的影响

目的:探讨血管紧张素Ⅱ(angiotensinⅡ,AngⅡ)对大鼠心肌成纤维细胞(cardiacfibroblasts,CFs)增殖的作用及其分子机制。方法:差速贴壁法体外培养新生Wistar大鼠的CFs,随机分为3组:对照组,AngⅡ处理组,洛沙坦(losartan)+AngⅡ处理组。作用24h后,收集细胞,倒置显微镜下观察活细胞形态;四氮唑盐(MTT)比色法检测细胞的增殖;流式细胞仪分析细胞周期与p21和p27的蛋白表达。结果:AngⅡ可显著提高CFsMTT-OD值,使S期细胞比率增加,G1期细胞比率下降,并降低细胞p27蛋白的表达,而对p21的蛋白表达无影响。AT1受体拮抗剂Losartan可完全阻断AngⅡ的作用。结论:AngⅡ通过AT1受体促进CFs增殖的机制可能与降低细胞p27蛋白的表达有关。     

异丙酚对血管紧张素Ⅱ诱导大鼠心肌成纤维细胞增殖的抑制作用及机制

目的探讨不同剂量异丙酚对血管紧张素Ⅱ(angiotensinⅡ, AngⅡ)诱导大鼠心肌成纤维细胞增殖的抑制作用和机制。方法 100只出生1~3 d的Wistar大鼠进行心肌成纤维细胞的分离与培养后,将细胞分为对照组(细胞培养基中加入1 mL含体积分数1%小牛血清的DMEM培养基)、AngⅡ组(细胞培养基中加入1 mL 1.0×10-7 mol/L AngⅡ),AngⅡ+异丙酚0.5 mmol/L组(细胞培养基中加入1 mL 1.0×10-7 mol/L AngⅡ+0.5 mmol/L异丙酚)、AngⅡ+异丙酚1.0 mmol/L组(细胞培养基中加入1 mL 1.0×10-7 mol/L AngⅡ+1.0 mmol/L异丙酚)、AngⅡ+异丙酚1.5 mmol/L组(细胞培养基中加入1 mL 1.0×10-7 mol/L AngⅡ+1.5 mmol/L异丙酚)。采用MTT法检测各组细胞生长抑制率,采用PCR法检测各组细胞α-SMA mRNA相对表达量,采用Western blot法检测各组细胞总蛋白含量。结果培养48 h,AngⅡ组细胞生长抑制率[(14.23±1.17)%]低于对照组[(23.32±2.15)%]、AngⅡ+异丙酚0.5 mmol/L组[(24.19±1.36)%]、AngⅡ+异丙酚1.0 mmol/L组[(29.25±2.30)%]及AngⅡ+异丙酚1.5 mmol/L组[(31.37±2.19)%](P<0.05),AngⅡ+异丙酚1.5 mmol/L组、AngⅡ+异丙酚1.0 mmol/L组、AngⅡ+异丙酚0.5 mmol/L组细胞生长抑制率依次降低(P<0.05);AngⅡ组心肌成纤维细胞α-SMA mRNA相对表达量(2.05±0.23)、总蛋白含量(225.06±18.66)均高于对照组(0.98±0.12、150.65±11.23)、AngⅡ+异丙酚0.5 mmol/L组(1.78±0.25、197.54±11.56)、AngⅡ+异丙酚1.0 mmol/L组(1.50±0.11、182.51±10.14)和AngⅡ+异丙酚1.5 mmol/L组(1.12±0.05、168.26±11.05)(P<0.05),AngⅡ+异丙酚0.5 mmol/L组、AngⅡ+异丙酚1.0 mmol/L组、AngⅡ+异丙酚1.5 mmol/L组及对照组心肌成纤维细胞α-SMA mRNA相对表达量及总蛋白含量依次降低(P<0.05)。结论异丙酚具有抑制AngⅡ诱导的大鼠心肌成纤维细胞增殖的作用,且随剂量增加,抗心肌成纤维的作用逐渐增强。     

双氢青蒿素对血管紧张素Ⅱ诱导的心肌成纤维细胞增殖和活性的影响

目的 探讨双氢青蒿素（DHA）对血管紧张素Ⅱ（AngⅡ）诱导的心肌成纤维细胞增殖和分泌活性的影响。方法 以乳鼠的心肌组织中的成纤维细胞为研究对象。实验设置为：对照组、AngⅡ组、DHA组和DHA+AngⅡ组,采用噻唑兰法检测每组细胞的增殖情况;用ELISA分析细胞孵育液中所含的Ⅰ型胶原蛋白（ColⅠ）以及纤黏连蛋白（FN）的水平;免疫印迹法分析胞质内的α-平滑肌肌动蛋白（α-SMA）和转化生长因子β1(TGF-β1)的含量。结果DHA组的细胞数、细胞悬浮液中ColⅠ和FN含量、细胞中α-SMA和TGF-β1蛋白含量与对照组相比均没有显著差异（P>0.05）。与对照组相比,AngⅡ组细胞（0.1272±0.0026）显著增殖（P<0.05）;细胞悬浮液中ColⅠ（0.8397±0.0371）和FN(0.7555±0.0820)含量均增加（P<0.05）;胞质内α-SMA(0.229±0.029)和TGF-β1(0.193±0.023)的量增多（P<0.05）。与AngⅡ组相比,DHA+AngⅡ组的细胞数量（0.1201±0.0021）显著下降;细胞悬浮液中ColⅠ...     

高血压心肌纤维化的发病机制：成纤维细胞在血管紧张素Ⅱ刺激下单核细胞趋化蛋白-1的表达状况

目的：研究成年大鼠心脏成纤维细胞(cardiac fibroblasts，CFs)在血管紧张素Ⅱ刺激下单核细胞趋化蛋白-1(monocyte chemotaxia protein-1，MCP-1)表达情况，探讨高血压合并心脏损害的可能机制，方法：成年大鼠CFs体外培养，在不同浓度血管紧张素Ⅱ不同作用时间刺激下，应用免疫蛋白印迹法和ELISA法分别测定细胞中和培养上清中MCP-1的含量。结果：①在细胞内和培养上清中均有MCP-1表达。②随着血管紧张素Ⅱ、刺激浓度的增加和刺激时间的延长，细胞内和上清中MCP-1的表达量也逐渐增加。在1&;#215;10^-11，1&;#215;10^-9，1&;#215;10^-8，1&;#215;10^-7，1&;#215;10^-6mol／L的血管紧张素Ⅱ作用下，上清中MCP-1的含量分别为(1．60&;#177;0．21)，(3．18&;#177;0．15)．(4．70&;#177;0．22)，(9．18&;#177;0．52)，(8．75&;#177;0．42)μg／L，与对照组(1．13&;#177;0．09)μg／L比较，除1&;#215;10^-11mol／L组外，差异均有显著性意义(t=26．21-39．67．P均&;lt;0．05)。③在1&;#215;10^-7mol／L的血管紧张素Ⅱ作用下，3，6，12和24h MCP-1的表达量分别为(2．13&;#177;0．31)，(3．25&;#177;0．20)．(5．28&;#177;0．50)和(9．18&;#177;0.52)μg／L，与空白对照组(1.13&;#177;0．09)μg／L比较差异均有显著性意义(t=6.93～34．11，P均&;lt;0．05)。结论：成年大鼠CFs的MCP-1的表达对血管紧张素Ⅱ的刺激有浓度和时间依赖性。CFs的MCP-1的表达可能参与高血压时心肌内的炎性反应和心肌纤维化。     

血管紧张素Ⅱ参与肾间质成纤维细胞自分泌TGF- β1 的实验研究

目的通过观察血管紧张素Ⅱ（AngiotensinⅡ,AngⅡ）对正常大鼠肾间质成纤维细胞株NRK．49F自分泌TGF- β1 的影响,探讨其参与肾小管间质纤维化的作用机制。方法用不同浓度Ang1I（10^-6,10^-7,10^-8, 10^-9mol／L）刺激NRK．49F（6h,12h,24h,和48h）。蛋白免疫印迹法检测TGF- β1 受体（T13RD的表达。ELISA方法检测细胞上清液中TGF-1的浓度。结果（1）AngⅡ（10^-7mol／L）能刺激NRK-49F细胞分泌TGF- β1 ,其表达量在刺激细胞6h后即开始增加,12h后达到峰值,24h和48h仍能维持较高的水平;（2）AngⅡ（10-9mol／L）能够上调NRK．49F细胞TBRI的表达。结论AngⅡ参与肾问质成纤维细胞自分泌TGF- β1 ,从而促进。肾小管问质纤维化的发生发展。     

高血压心肌纤维化的发病机制:成纤维细胞在血管紧张素Ⅱ刺激下单核细胞趋化蛋白-1的表达状况

目的:研究成年大鼠心脏成纤维细胞(cardiac fibroblasts,CFs)在血管紧张素Ⅱ刺激下单核细胞趋化蛋白-1(monocyte chemotaxia protein-1,MCP-1)表达情况,探讨高血压合并心脏损害的可能机制。 方法:成年大鼠CFs体外培养,在不同浓度血管紧张素Ⅱ不同作用时间刺激下,应用免疫蛋白印迹法和ELISA法分别测定细胞中和培养上清中MCP-1的含量。 结果:①在细胞内和培养上清中均有MCP-1表达。②随着血管紧张素Ⅱ、刺激浓度的增加和刺激时间的延长,细胞内和上清中MCP-1的表达量也逐渐增加。在1×10~(-11),1×10~(-9),1×10~(-8),1×10~(-7),1×10~(-6)mol/L的血管紧张素Ⅱ作用下,上清中MCP-1的含量分别为(1.60±0.21),(3.18±0.15),(4.70±0.22),(9.18±0.52),(8.75±0.42)μg/L,与对照组(1.13±0.09)μg/L比较,除1×10~(-11)mol/L组外,差异均有显著性意义(t=26.21～39.67,P<均0.05)。③在1×10~(-7)mol/L的血管紧张素Ⅱ作用下,3,6,12和24h MCP-1的表达量分别为(2.13±0.31),(3.25±0.20),(5.28±0.50)和(9.18±0.52)μg/L,与空白对照组(1.13±0.09)μg/L比较差异均有显著性意义(t=6.93～34.11,P均<0.05)。 结论:成年大鼠CFs的MCP-1的表达对血管紧张素Ⅱ的刺激有浓度和时间依赖性。CFs的MCP-1的表达可能参与高血压时     

肾上腺髓质素N端20肽对血管紧张素Ⅱ刺激心肌成纤维细胞增殖、胶原合成的影响

目的:探讨肾上腺髓质素N端20肽(PAMP)对血管紧张素Ⅱ(angotesinⅡ,AngⅡ)刺激心肌成纤维细胞(CFs)增殖及胶原生成的影响。方法:采用胰酶消化、差速贴壁法培养新生SD大鼠CFs,以3H脯氨酸掺入法测定胶原合成、四氮唑盐(MTT)比色法测定细胞数目,分别观察不同浓度的PAMP、AngⅡ、及PAMP对ANGⅡ诱导CFs增生及胶原合成作用的影响。实验分组(1)空白对照组;(2)10-9、10-8、10-7、10-6mol/LAngⅡ组;(3)10-9、10-8、10-7、10-6mol/LPAMP组;(4)10-7mol/LAngⅡ+PAMP(10-9、10-8、10-7、10-6mol/L)组。结果:(1)随着PAMP浓度的增高,MTT比色值差异无显著性(F=10.21,P>0.05)。随着AngⅡ浓度的增高,MTT比色值也明显增高,各组间差异有显著性(P值均<0.01)。PAMP+AngⅡ组,随着PAMP浓度的增高,MTT比色值均显著降低(P<0.01)。(2)PAMP组的3H脯氨酸掺入率与对照组相比(F=16.92,P>0.05),各组之间差异无显著性。随着AngⅡ浓度的增高,CFs的3H脯...     

白藜芦醇抑制血管紧张素Ⅱ诱导的大鼠心肌成纤维细胞分化的作用和机制

目的研究白藜芦醇(resveratrol,Res)对血管紧张素Ⅱ(angiotension AngⅡ)诱导的心肌成纤维细胞增殖和分化的影响,探讨其抗心肌纤维化的作用及其机制。方法将细胞分为对照组、AngⅡ模型组和Res组。分别用ELISA法检测胶原蛋白collagen I和collagenⅢ含量;采用Western blot法检测PCNA、α-SMA、TGF-β1、TGF-βRⅡ、Smad3、Smad7蛋白含量。结果与对照组相比,AngⅡ可明显诱导细胞中PCNA、α-SMA含量增多、细胞培养基中胶原蛋白collagen I、collagenⅢ含量增加、TGF-β1和TGF-βRⅡ、Smad3蛋白水平增多,降低Smad7蛋白含量;而Res可明显改善上述指标。结论Res抗心肌纤维化的作用可能与其抑制AngⅡ诱导的心肌成纤维细胞的增殖和分化,下调TGF-β1/Smads信号通路有关。     

大鼠颅脑损伤后心肌损害及血浆和心肌血管紧张素的变化

背景：颅脑损伤可以引起一系列的内脏并发症，其中心血管并发症日益引起人们的重视。目的：探讨颅脑损伤所致循环和心脏局部血管紧张素Ⅱ及心脏局部血管紧张素Ⅱ1型受体水平的变化。设计：随机对照动物实验。单位：首都医科大学附属北京天坛医院和首都医科大学基础医学院。材料：实验于2003／2004在首都医科大学中心实验室和北京天坛医院中心实验室进行。健康雌性Wistar大鼠40只，随机分为颅脑损伤组和对照组两组，每组20只。方法：颅脑损伤组用局部重物撞击法建立大鼠颅脑损伤模型，对照组不打击。在撞击即时点后24h取材，每组10只用于血管紧张素Ⅱ及其1型受体检测，另外10只用于心肌病例形态观察。主要观察指标：①用均相竞争放免法测定血浆血管紧张素Ⅱ水平。②采用免疫组织化学方法检测心肌血管紧张素Ⅱ及其1型受体的表达。③采用酶反应速率法测定血清肌酸磷酸激酶同工酶活性。④苏木精-伊红染色，光镜，透射电镜观察大鼠心肌超微结构等病理形态学改变。结果：40只大鼠进入结果分析。①血浆血管紧张素Ⅱ水平：颅脑损伤组明显高于对照组[（965．52&;#177;176．71），（485．03&;#177;86．13）ng／L，P〈0．05]。②血清肌酸磷酸激酶同工酶活性：颅脑损伤组显著高于对照组[（12．77&;#177;4．07），（3．49&;#177;1．55）μkat／L，P〈0．05]。③心肌血管紧张素Ⅱ及其1型受体的表达：颅脑损伤组的阳性反应物面积与灰度值均高于对照组（P〈0．05）。④苏木精-伊红染色颅脑损伤组心肌细胞胞浆强嗜酸性染色。明显的胞质皱缩，肌纤维断裂、减少或消失，可见心肌局灶性水样变性、溶解或坏死。超微结构的病理观察均见心肌病理损害。结论：大鼠颅脑损伤可导致心肌损害的发生，血管紧张素系统变化可能是其因素之一。     

Exaggerated nociceptive responses on morphine withdrawal: roles of protein kinase C epsilon and gamma

On withdrawal from opioids many patients experience a heightened sensitivity to stimuli and an exaggerated pain response. The phenomenon has been little studied in infants. We present evidence that in postnatal day 7 rats an exaggerated nociceptive ventral root response of spinal cords in vitro and withdrawal-associated thermal hyperalgesia in vivo are dependent on protein kinase C (PKC), and we document the roles of PKC and gamma isozymes. In vitro, the slow ventral root potential (sVRP) is a nociceptive-related response in spinal cord that is depressed by morphine and recovers to levels significantly above control on administration of naloxone. A broad-spectrum PKC antagonist, GF109213X, blocked withdrawal hyperresponsiveness of the sVRP whereas an antagonist specific to Ca(++)-dependent isozymes, Go69076, did not. Consistent with this finding, a specific peptide inhibitor of calcium-independent PKC, but not an inhibitor of calcium-dependent PKC gamma, blocked withdrawal hyperresponsiveness of the sVRP. Similarly, in vivo in 7-day-old rat pups, inhibition of PKC, but not PKC gamma, prevented thermal hyperalgesia precipitated by naloxone at 30 min post-morphine. In contrast, thermal hyperalgesia during spontaneous withdrawal was inhibited by both PKC and gamma inhibitors. The consistency between the in vivo and in vitro findings with respect to naloxone-precipitated withdrawal provides further evidence that the sVRP reflects nociceptive neurotransmission. In addition the difference between naloxone-precipitated and spontaneous withdrawal in vivo suggests that in postnatal day 7 rats, morphine exposure produces an early phase of primary afferent sensitization dependent upon PKC translocation, followed by a later phase involving spinal sensitization mediated by PKC gamma.     

NAD(P)H-dependent superoxide production in platelets: the role of angiotensin II and protein kinase C

OBJECTIVES: Vascular NAD(P)H oxidase represents a major source for excessive superoxide production in hypertension. Angiotensin II (AngII) can activate NAD(P)H oxidase via the angiotensin II type 1 (AT1) receptor and protein kinase C (PKC). Platelets possess AT1 receptors and all the components of the NAD(P)H oxidase system. We employed this tissue model to explore mechanisms involved in AngII-mediated superoxide production. DESIGN AND METHODS: Platelet suspensions from hypertensive patients' blood were activated with AngII or phorbol 12-myristate 13-acetate (PMA). Inhibitors of NAD(P)H oxidase, PKC, and the AT1 receptor were employed to study their effects on superoxide production. RESULTS: Superoxide production was stimulated by AngII and PMA and attenuated by AT1 receptor antagonists (mean percentage reduction 80.2%, P<0.01) and inhibitors of PKC (mean reduction 94.8%, P<0.001) and NAD(P)H oxidase (mean reduction 100%, P< 0.001). CONCLUSIONS: AngII stimulates platelet superoxide production through activation of vascular NAD(P)H oxidase via the AT1 receptor and PKC.     

Formation of protein kinase C(epsilon)-Lck signaling modules confers cardioprotection

The epsilon isoform of protein kinase C (PKCepsilon) is a member of the PKC family of serine/threonine kinases and plays a critical role in protection against ischemic injury in multiple organs. Functional proteomic analyses of PKCepsilon signaling show that this isozyme forms multiprotein complexes in the heart; however, the precise signaling mechanisms whereby PKCepsilon orchestrates cardioprotection are poorly understood. Here we report that Lck, a member of the Src family of tyrosine kinases, forms a functional signaling module with PKCepsilon. In cardiac cells, PKCepsilon interacts with, phosphorylates, and activates Lck. In vivo studies showed that cardioprotection elicited either by cardiac-specific transgenic activation of PKCepsilon or by ischemic preconditioning enhances the formation of PKCepsilon-Lck modules. Disruption of these modules, via ablation of the Lck gene, abrogated the infarct-sparing effects of these two forms of cardioprotection, indicating that the formation of PKCepsilon-Lck signaling modules is required for the manifestation of a cardioprotective phenotype. These findings demonstrate, for the first time to our knowledge, that the assembly of a module (PKCepsilon-Lck) is an obligatory step in the signal transduction that results in a specific phenotype. Thus, PKCepsilon-Lck modules may serve as novel therapeutic targets for the prevention of ischemic injury.     

Variable expression of protein kinase C epsilon in human melanoma cells regulates sensitivity to TRAIL-induced apoptosis

Protein kinase C (PKC) activation is believed to protect against apoptosis induced by death receptors. We have found however that the effect of activation of PKC on tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis of melanoma differs between cell lines. Pretreatment with phorbol 12-myristate 13-acetate (PMA) led to inhibition of apoptosis in the majority of the melanoma cell lines, but those with relatively low PKC epsilon expression were sensitized to TRAIL-induced apoptosis. Introduction of PKC epsilon into PKC epsilon-low cell lines reversed sensitization of the cells to TRAIL-induced apoptosis by PMA. In contrast, a dominant-negative form of PKC epsilon caused an increase in sensitivity. The changes in sensitivity to TRAIL-induced apoptosis were reflected in similar changes in conformation of Bax and its relocation from the cytosol to mitochondria. Similarly, there were concordant increases or decreases in mitochondrial release of second mitochondria-derived activator of caspase/DIABLO, activation of caspase-3, and processing of its substrates. Activation of PKC seemed to mediate its effects upstream of mitochondria but downstream of caspase-8 and Bid in that pretreatment with PMA did not cause significant changes in the expression levels of TRAIL death receptors, alterations in the levels of caspase-8 activation, or cleavage of Bid. PKC activated the anti-apoptotic extracellular signal-regulated kinase 1/2 pathway, but inhibitors of this pathway only partially reversed the protective effect of PKC against TRAIL-induced apoptosis. These results provide further insights into the variable responses of melanoma to TRAIL-induced apoptosis and may help define responsive phenotypes to treatment of melanoma with TRAIL.     

Communication between myocytes and fibroblasts in cardiac remodeling in angiotensin chimeric mice

To characterize the mode of action of angiotensin II (Ang II) in cardiac remodeling, we generated chimeric mice that are made of both homozygous Ang II receptor type 1A gene (Agtr1a) null mutant cells and Agtr1a intact cells expressing the lacZ gene (ROSA26). Both Agtr1a null and intact myocytes and interstitial cells independently form areas that are randomly distributed throughout the heart. The distribution of ROSA26 cardiomyocytes overlaps completely with that of Ang II binding, indicating that the majority of Ang II receptors reside on cardiomyocytes. When Ang II (1 ng/g body weight/min) was infused for 2 weeks, mice developed mild to moderate hypertension. The proliferating cardiac fibroblasts identified by bromodeoxyuridine staining were present predominantly in the areas surrounded by Agtr1a intact cardiomyocytes. When control chimeric mice made of wild-type cells and ROSA26 cells (i.e., both carrying intact Agtr1a) were infused with Ang II, fibroblast proliferation was found equally in these cardiomyocyte types. When compared with Agtr1a null mutant chimeras, the control chimeras had more extensive cardiac fibrosis, most prominently in perivascular regions. Therefore, in response to Ang II, cardiac fibroblasts proliferate through both the local and systemic action of Ang II. Importantly, the former is determined by the Ang II receptor of neighboring cardiomyocytes, indicating that a communication between myocytes and fibroblasts plays an important role during Ang II-dependent cardiac remodeling.     

Ethanol withdrawal-associated allodynia and hyperalgesia: age-dependent regulation by protein kinase C epsilon and gamma isoenzymes.

Ethanol (EtOH) withdrawal increases sensitivity to painful stimuli in adult rats. In this study, withdrawal from a single, acute administration of EtOH dose-dependently produced mechanical allodynia and thermal hyperalgesia in postnatal day 7 (P7) rats. In contrast, P21 rats exhibited earlier and more prolonged mechanical allodynia but not thermal hyperalgesia. For both P7 and P21 rats, blood and spinal cord EtOH levels peaked at 30 minutes after administration, with P7 rats achieving overall higher spinal cord concentrations. Protein kinase C (PKC) has been implicated in mediating pain responses. Inhibitory PKC- and gamma-specific peptides attenuated mechanical allodynia and thermal hyperalgesia in P7 rats, whereas only the PKCgamma inhibitor prevented mechanical allodynia in P21 rats. Immunoreactive PKC in dorsal root ganglion and PKCgamma in lumbar spinal cord increased at 6 hours after EtOH administration in P7 rats. In P21 rats, the density of PKC immunoreactivity remained unchanged, whereas the density of PKCgamma immunoreactivity increased and translocation occurred. These studies demonstrate developmental differences in neonatal nociceptive responses after withdrawal from acute EtOH and implicate a role for specific PKC isozymes in EtOH withdrawal-associated allodynia and hyperalgesia. PERSPECTIVE: This study examines age-specific nociceptive responses after ethanol exposure by using 2 different ages of rats. The results suggest that ethanol age-dependently alters sensitivity to mechanical and thermal stimuli via specific protein kinase C isozymes. These results begin to ascertain the mechanisms that produce abnormal pain after alcohol exposure.     

蛋白激酶C-alpha和beta在血压及肾小球滤过功能中的作用比较

目的明确蛋白激酶C（PKC）-alpha和beta在小鼠血压及肾小球滤过功能中的不同作用。方法使用代谢箱收集正常饮食下PKC—alpha和beta两种基因敲击鼠及相应野生鼠24h尿液,采用间接免疫酶联吸附法（ELISA）检测血清及24h尿白蛋白排泄情况,3[H]标记的菊粉作清除率试验并观察小鼠血压。结果与野生鼠相比,正常饮食下PKC—alpha基因敲击鼠血压、尿白蛋白正常,肾小球滤过率（GFR）减少（P=0．02）,而PKC—beta基因敲击鼠尿白蛋白、GFR正常,血压上升（P=0．03）。结论PKC—alpha主要参与调节肾小球的滤过功能,而PKC—beta主要参与调节动脉血压,每一亚基的具体作用不能被另一亚基取代。