DEVELOPMENT OF A NEW EXPERIMENTAL APPARATUS FOR STUDYING OF MECHANICAL ACTIVITY OF ISOLATED ARTERIOLES.

点击翻译按钮获取中文摘要

[1] DEVELOPMENT OF A NEW EXPERIMENTAL APPARATUS FOR STUDYING OF MECHANICAL ACTIVITY OF ISOLATED ARTERIOLESPreparation and dissectionExperimental materials, i. e., brain, spinal cord, or chick pouch, were rapidly removed and placed in a cooled dissection chamber filled with MOPS-buffered physiological salt solution containing 1% BSA.The chamber is placed on a recessed Plexiglas well, and chilled fluid is circulated through the well jacket from a cooling thermopump. The isolated arteriole was carefully transferred from the dissection chamber to a temperature-controlled cannulation chamber mounted on a stage of an inverted microscope.CannulationThe isolated arteriole was cannulated at both ends by using a system of concentric glass pipettes mounted on a micromanipulator which was equipped on the stage of the inserted microscope. By applying vacuum to the lumen of the holding pipette, one end of the arteriole was gently pulled into the pipette. The perfusion pipette was inserted into the l … More umen of the arteriole. Then the other end of the arteriole was cannulated in the same manner.InstrumentationAfter the cannulation, both micropipettes were connected to water manometers used to adjust intraluminal pressure via independent reservoirs. Another fluid reservoir pressurized by the manometer could be inserted into the fluid path between the arteriole and the upstream reservoir by menas of a three-way liquid switch.The image of the cannulated arteriole was recorded using a video camera and displayd on a television monitor. Arteriolar luminal diameters were measured manually using a video caliper incorporated with MacLab Chart data acquisition system.[2] PHYSIOLOGICAL APPLICATIONWe investigated the responses of isolated rabbit spinal arterioles to flow with special reference to endogenous nitric oxide (NO) and prostaglandins (PGs). The arterioles (-100mum in diameter) were cannulated at both ends with microglass pipettes, and perfused at constant pressure (-60mmHg). The arterioles developed spontaneous tone at 37ﾟC by -26% of their maximum dilation. Treatment with indomethacin (10mum) produced a significant decrease in the arteriolar diameter, whereas treatment with a nitric oxide production inhibitor (L-NAME) produced no significant change. In the presence of 10muM indomethacin, however, 30muM L-NAME caused a marked decrease in the arteriolar diameter, which was completely reversed with additional administration of 1mM L-arginine. These findings suggest that both NO and vasodilative PGs released from the endothelial cells may play important roles in the flow-mediated vasodilation in the rabbit spinal arterioles. Less