A correlative study of myocardial relaxation, intracellular Ca^<2+> concentration, expression of the sarcoplasmic reticulum Ca^<2+>-ATPase.

心肌舒张与细胞内Ca^2浓度、肌浆网Ca^2-ATP酶表达的相关性研究。

• 批准号: 03670440
• 负责人: MOMOMURA Shin-ichi
• 金额: $ 1.34万
• 依托单位: University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1991
• 资助国家: 日本
• 起止时间: 1991 至 1993
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-03670440/
• 关键词: Cardiac myocyte; Myocardial hypertrophy; Myocardial relaxation; Intracellular Ca^<2+>-handling; Sarcoplasmic reticulum Ca^<2+>-ATPase; Na^+; Ca^<2+> exchanger; RNA blot analysis; Na^+-Ca^<2+>交換機構; 電位依存性Ca^<2+>チャンネル; RNAブロット解析; 筋小胞体Ca^<2+>ーATPas

Intracellular Ca^<2+>-hadling has been reported to be altered along with myocardial hypertrophy. To well characterize the altered Ca^<2+>-handling in hypertrophied cardiac myocytes, an in vitro model of myocardial hypertrophy was created in cultured chick embryo (10-day-old) ventricular myocytes by exposure to 10% fetal calf serum (FCS) for 24 hours. In the FCS-treated group, both RNA and protein contents increased by about 25% as compared with the untreated control group (p<0.05, n=4), without any changes in cell number. The peak systolic [Ca^<2+>]_i (measured with indo-1) was lower (753<plus-minus>103 vs. 950<plus-minus>142 ms, p<0.050, n=4) and T_<1/2> of the decay of the Ca^<2+> transients was longer (163<plus-minus>7 vs.132<plus-minus>12 msec, p<0.05, n=4) in the FCS-treated group than in the control group. Thapsigargin (1 mM), an inhibitor of the sarcoplasmic reticulm (SR) Ca^<2+>-ATPase, induced a decrease in the peak systolic [Ca^<2+>]_i with an elongation of the T_<1/2> as obs … More erved in the FCS-treated group. RNA blot analysis revealed that the relative abundance of mRNA (determined by laser densitometry) encoding the SR Ca^<2+>-ATPase was decreased significantly (41.8<plus-minus>3.8% of the control group, p<0.05, n=4) in the FCS-treated group. The levels of Na^+/Ca^<2+> exchanger mRNA were also diminished in the FCS-treated group (35.0<plus-minus>4.3% of the control, p<0.05, n=4). Steady-state levels of [Ca^<2+>]_i during perfusion with Na^+-free solution including 10 mM caffeine (ONa+Caf), which blocks Na^+/Ca^<2+> exchanger and SR,was lower in the FCS-treated group (338<plus-minus>30 vs. 806<plus-minus>129 nM,p<0.05, n=4). When verapamil (1 mM) perfusion was followed, these differences were diminished (294<plus-minus>33 vs. 282<plus-minus>35 nM,NS). Perfusion with ONa+Caf after pretreatment with 1 mM vanadate (used as an inhibitor of the sarcolemmal Ca^<2+>-ATPase) also showed similar results. On the other hand, pretreatment with verapamil caused no significant differences in the steady-state [Ca^<2+>]_i during perfusion with ONa+Caf between the FCS-treated and control groups. These data suggest that the alterations in Ca^<2+>-handling occur along with cellular hypertrophy in our in vitro model. These changes in Ca^<2+>-handling may include down regulation of voltage-dependent Ca^<2+> channel as well as the SR Ca^<2+>-ATPase and Na^+/Ca^<2+> exchanger. Less

据报道，随着心肌肥厚，细胞内钙离子浓度也会发生改变。为了更好地研究肥大心肌细胞内钙离子的变化，用10%胎牛血清(FCS)作用于体外培养的10日龄鸡胚心肌细胞，建立了心肌肥厚模型。在FCS处理组，RNA和蛋白质含量均比未处理对照组增加了约25%(p&lt；0.05，n=4)，但细胞数量没有变化。用INDO-1测量的收缩峰值[Ca^&lt；2+>]_i较低(753；正负103vs.950&lt；正负142ms，p&lt；0.050，n=4)，而T_lt；1/2&gt；较长(163&lt；正负；7vs.132&lt；正负；12ms，p&lt；0.05，n=4)。肌浆网(SR)Ca^&lt；2+&gt；-ATPase抑制剂thapsigargin(1 MM)引起收缩峰值[Ca^&lt；2+]_i降低，T_1/2&gt；AS OBS…延长。FCS治疗组的勃起功能更强。RNA印迹分析显示，FCS处理组SRCa^&lt；2+&gt；-ATPase的相对丰度显著降低(41.8&lt；正负-3.8%，p&lt；0.05，n=4)。FCS处理组大鼠心肌细胞Na~+/Ca~(2+)/Ca~(2+)交换基因表达水平也明显降低(为对照组的4.3%，p&lt；0.05，n=4)。在含10 mM咖啡因(ONA+Caf)的无钠溶液(ONA+Caf)灌流期间，FCS治疗组的稳态[Ca^&lt；2+&gt；]_i水平较低(338&lt；+-gt；30vs.806&lt；129 nM，p&lt；0.05，n=4)。当维拉帕米(1 Mm)灌流后，这些差异减小(294；+-gt；33vs.282&lt；+-gt；35 nM，NS)。在1 mM钒酸盐(用作肌膜Ca^&lt；2+&Gt；-ATPase的抑制剂)预处理后，用ONA+Caf灌流也有类似的结果。另一方面，维拉帕米对ONA+Caf灌流的稳态[Ca~(2+)]_i无明显影响。这些数据表明，在我们的体外模型中，随着细胞肥大，钙离子处理的变化也会发生。钙离子转运的这些变化可能包括电压依赖性钙离子通道的下调，以及SR钙离子/钙离子交换器的下调。较少

项目成果

Kinugawa K,Takahashi T,Kohmoto O,Yao A,Momomura S,Serizawa T.: "Altered Ca^<2+>-handling during cellular hypertrophy in cultured chick ventricular myocytes." In The Adapted Heart. Nagano M,Takeda N,Dhalla NS,editors. Raven Press, New York. (in press).

Kinukawa K、Takahashi T、Kohmoto O、Yao A、Momomura S、Serizawa T.：“培养鸡心室肌细胞细胞肥大过程中 Ca^2-处理的改变。”

K.Kinugawa,et.al.: "Altered Ca^<2+>-handling during cellular hypertrophy in cultured chick ventricular myocytes.In The Adapted Heart." Raven Press,New York(印刷中),

K. Kinukawa 等人：“培养鸡心室肌细胞细胞肥大过程中 Ca^2+-处理的改变。In The Adapted Heart，纽约（正在出版），

Kinugawa K,Takahashi T,Kohmoto O,Yao A,Momomura S,Serizawa T.: "Altered Ca^<2+>-handling during cellular hypertrophy in cultured chick ventricular myocytes.In The Asapted Heart.Nagano M,Takeda N,Dhalla NS,editors." Raven Press,New York(in press),

Kinukawa K，Takahashi T，Kohmoto O，Yao A，Momomura S，Serizawa T.：“培养鸡心室肌细胞细胞肥大期间改变 Ca^<2>-处理。在 Asapted Heart.Nagano M，Takeda N，Dhalla NS