Roles of c-kit in functional development of Ca^<2+> release mechanism in smooth muscle cells

c-kit在平滑肌细胞Ca^2释放机制功能发育中的作用

基本信息

批准号：
11670094
负责人：
TOKUTOMI Yoshiko
金额：
$ 2.3万
依托单位：
KUMAMOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

项目摘要

To clarify the roles of c-kit, a receptor-type tyrosine kinase, in the functional development of smooth muscle cells, we investigated the property of the Ca^<2+>-induced Ca^<2+> release in smooth muscle cells freshly dissociated from gastrointestinal tract of BALB/c mice treated with neutralizing anti-c-kit-monoclonal antibody (ACK2). Under voltage-clamped conditions with the nystatin-perforated patch-clamp technique, c-kit-expressing (c-kit^+) cells developed rhythmic Ca^<2+>-activated Cl^- currents and smooth muscle cells from the control animals developed spontaneous outward currents and caffeine-and carbachol-induced transient outward currents. In smooth muscle cells from the ACK2-treated mice, dysfunction in the ryanodine-sensitive Ca^<2+> storage in the cytoplasm was suggested when tested with caffeine-induced Ca^<2+>-activated K^+ currents and fura-2 fluorometric measurements of intracellular Ca^<2+> concentration. The Ca^<2+> release and caffeine-induced Ca^<2+>-activated K^+ currents in smooth muscle cells from the control animals were ryanodine-sensitive and had great dependence upon the activity of L-type voltage-gated Ca^<2+> channels. In measurements of isometric tension, caffeine-induced relaxation was significantly accelerated in smooth muscles precontracted with high K^+ depolarization or carbachol. Altogether, it is suggested that ryanodine-sensitive Ca^<2+> release is an important modifier of Ca^<2+> homeostasis in the cytoplasm and the contractility of gastrointestinal smooth muscle of mice and that the c-kit^+ cells play important roles in the development of smooth muscle through the rhythmic excitation and Ca^<2+>-fluctuation in the cytoplasm.

为了阐明受体型酪氨酸激酶c-kit在平滑肌细胞功能发育中的作用，我们研究了平滑肌细胞中Ca^<2+>诱导Ca^<2+>释放的特性新鲜分离自经中和抗 c-kit 单克隆抗体 (ACK2) 处理的 BALB/c 小鼠胃肠道。在使用制霉菌素穿孔膜片钳技术的电压钳条件下，表达c-kit的(c-kit^+)细胞产生有节律的Ca^<2+>-激活的Cl^-电流和来自对照动物的平滑肌细胞产生自发的外向电流以及咖啡因和卡巴胆碱引起的瞬时外向电流。在来自ACK2处理的小鼠的平滑肌细胞中，当用咖啡因诱导的Ca ^ 2+ 激活的K ^+ 电流和fura-进行测试时，表明细胞质中兰尼碱敏感的Ca ^ 2+ 储存功能障碍。 2细胞内Ca 2+ 浓度的荧光测量。对照动物的平滑肌细胞中的Ca ^ 2+ 释放和咖啡因诱导的Ca ^ 2+ 激活的K ^+ 电流是兰尼碱敏感的，并且对L型电压门控的活性有很大依赖性。 Ca^<2+>通道。在等长张力的测量中，在用高 K^+ 去极化或卡巴胆碱预收缩的平滑肌中，咖啡因诱导的松弛显着加速。总而言之，表明兰尼碱敏感的 Ca^<2+> 释放是小鼠细胞质中 Ca^<2+> 稳态和胃肠道平滑肌收缩性的重要调节剂，并且 c-kit^+ 细胞发挥着重要作用。通过细胞质中的节律性兴奋和Ca^2+-波动在平滑肌的发育中发挥重要作用。