| Budget Amount *help |
¥7,300,000 (Direct Cost: ¥7,300,000)
Fiscal Year 1995: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1994: ¥5,700,000 (Direct Cost: ¥5,700,000)
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| Research Abstract |
This study examined the role of nerves, endothelium and blood cells on the tone of microvessels. TO persuade this protocol there are some problems using the instrument to mounting the microvessels. There are many literatures to use this instrument. However, we found that there is an inhomogeneity of temperature within the bath that is not good for the experiment. Firstly, we changed the bath capacity to 1 ml and kept the bath temperature within 0.5C.Secondly, we did not perfuse the fluid within the lumen of the vessels, because we could not get the constant flow. Thirdly, in experiment for the effect of blood cells on the tone of microvessels we changed the experimental protocol : 1.We administered white blood cell (WBC) directly to the bath. 2.We used specially designed bath, in which temperature was kept constant 37C by heating with Nichrome wire. 3.We used the Hepes buffer solution instead of Krebs solution, since aeration of Krebs solution disturbed the measurement of diameter of m
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icrovesses. Aeration with 5% carbon dioxide is necessary to keep the pH of Krebs solution 7.4. We used the above mentioned instruments and got the following results using porcine spinal and coronary vessels. 1.bradykinin is a useful drug to test the presence or absence of endothelium. 2.Transmural electrical stimulation (20mA,duration 0.3msec, 1Hz) induced a slight contraction. However, this contraction was not caused by norepinephrine, since directly applied norepinephrine induced dilation . Further study is necessary what transmitter may be invol ved in this contraction. 3.In coronary vessels, hypoxia potentiated the WBC-induced vasodilation. In antherior spinal artery, WBC,10^4 to 10^6 cells/ml, induced vasodilation . We could notmeasure the diameter of the microvessels in the presence of 10^7 WBC because of this opaque solution. 4.Carbon dioxide itself contracted spinal artery, whereas low pH (acidosis) dilated. From these findings it seems that the response of microvessels to various environmental changes was different from that of large vessels. Less
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