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Effects of extracellular ion on the intracellular calcium concentration and tension development of vascular smooth muscle

细胞外离子对血管平滑肌细胞内钙离子浓度及张力发展的影响

基本信息

批准号：
07680060
负责人：
ABE Shimako
金额：
$ 1.41万
依托单位：
Nakamura-Gakuen Junior College (1997)Nakamura Gakuen College (1995-1996)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1997
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07680060/
关键词：
Magnesium Vascular Smooth Musele Intracellular Calcium Concentration Fura PE3 Norepinephrine Caffein WKY SHR Fura-2

项目摘要

The aim of this experiment is to clarify the effect of extracellular magnesium (Mg) and calcium (Ca) ion on the intracellular calcium concentration ([Ca^<2+>]_i) and tension development of vascular smooth muscle.Male Wistar-Kyoto (WKY) or spontaneous hypertensive rats (SHR) were fed either a Mg-deficient diet (Mg-def) or a control diet (control) for two to threee weeks. The serum Mg concentration of the Mg-def rats were significantly lower than those observed in the control WKY or SHR rats. On the other hand, the serum Ca concentration of the Mg-def rats were significantly higher than those observed in the control WKY or SHR rats. A significant negative correlation was thus found between the serum Mg and Ca concentration.Using Front-surface fluorometry and fura PE3-loaded rat thoracic aortas, we simulataneously measured the [Ca^<2+>]_i level and tension development. In the presence of extracellular Ca^<2+>, vascular strips from the Mg-def rat showed greater increases in both the [Ca^<2+>]_i levels and tension development induced by norepinephrine (NE) than those observed in the control WKY rats. On the other hand, in the absence of extracellular Ca^<2+>, no differences were observed in the [Ca^<2+>]_i levels and tension development induced by NE or caffein (Caf) between the Mg-def and control WKY rats. In contrast, no significant differences were seen in the [Ca^<2+>]_i levels and tension development induced by NE or Caf regardless of the presence or absence of extracellular Ca^<2+> between the Mg-def and the control SHR.The resting levels of both [Ca^<2+>]_i and tension in the SHR rats were greater than in the WKY rats. Acetylcholine (Ach) induced an endothelium-dependent relaxation in vascular strips precontracted with NE.Howere, no significant differences were observed in the Ach-induced vasorelaxation between the Mg-def rats and the control WKY or SHR rats.

为探讨细胞外镁（Mg）和钙（Ca）离子对血管平滑肌细胞内钙离子浓度（[Ca^2+] i）和张力发展的影响，用缺镁饲料（Mg-def）或对照饲料（control）喂养雄性Wistar-Kyoto（WKY）和自发性高血压大鼠（SHR）2 ~ 3周。Mg-def大鼠血清镁浓度显著低于对照组WKY和SHR大鼠。另一方面，Mg-def大鼠的血清Ca浓度显著高于对照WKY或SHR大鼠。用荧光法和Fura PE_3负载的大鼠胸主动脉同时测定[Ca^<2+>]_i水平和张力发展。在细胞外Ca^<2+>存在的情况下，Mg-def大鼠血管条的[Ca^<2+]_i和去甲肾上腺素（NE）引起的张力发展均比对照WKY大鼠显著增加。另一方面，在细胞外Ca^<2+>缺乏的情况下，Mg-def和对照WKY大鼠之间的[Ca^<2+]_i水平和NE或咖啡因（Caf）诱导的张力发展没有差异。而Mg-def组和对照组SHR的静息[Ca^<2+>] i水平和NE或Caf引起的张力发展无显著差异，SHR组的静息[Ca^<2+>] i水平和张力水平均高于WKY组。乙酰胆碱（Ach）可引起NE预收缩血管条的内皮依赖性舒张反应，而Mg-def大鼠的Ach舒张反应与对照组WKY和SHR大鼠无显著差异。