1997 Fiscal Year Final Research Report Summary
Effects of extracellular ion on the intracellular calcium concentration and tension development of vascular smooth muscle
| Project/Area Number |
07680060
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
家政学
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| Research Institution | Nakamura-Gakuen Junior College (1997)
Nakamura Gakuen College (1995-1996) |
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Principal Investigator |
ABE Shimako Nakamura-Gakuen Junior College, Division of Food and Nutrition, Lecturer., 食物栄養科, 講師 (60192994)
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| Project Period (FY) |
1995 – 1997
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| Keywords | Magnesium / Vascular Smooth Musele / Intracellular Calcium Concentration / Fura PE3 / Norepinephrine / Caffein / WKY / SHR |
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| Research Abstract |
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.
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