Development of a new appratus for continuous recording of mechanical activity of isolated arterioles

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A.A camera-type diameter gauge was constructed and used in physiological experiments. The distinctive features of the design and use of the gauge may be summarized as follows. Installation of an image sensor in the focal plane of a single-lens reflex camera equipped with a set of extension tubes which makes it possible to measure outer diameters of blood and lymph vessels as small as 100 micrometer.Using the gauge, we can distinguish a diameter change of about 12 micrometer. Simultaneous measurements of the diameters of two different vessels can be made using two window signals generated independently at desired moments for appropriate periods within the video scans.B.Longitudinal strips isolated from dog distributing muscular arteries were relaxd by noradrenaline and contracted by papaverine. This paradoxical relaxation and contraction may be due to a helical and circular arrangement of smooth muscle in the wall which is incompressible. Various vasoconstrictive agents, including norad … More renaline, produced a circumferential contraction and longitudinal relaxation in muscular arteries. Vasodilator agents produced the opposite effect. The paradoxical responses led us to a new method in pharmacological research of small arteries. By the use of this method, we have successfully studied pharmacological responses of small arteries ranging from 0.3 to 0.5 mm in outer diameter.C.We have constructed a new appratus for continuous recording of mechanical activity of isolated arterioles ranging 0.05 to 0.15 mm in outer diameter. An arteriole was dissected free of many tissues using the method of Duling and Rivers (1986) . The vessel segment was then transferred to a 1-ml temperature-controlled chamber on the stage of an inverted microscope, cannulated at both ends of glass pipettes, and heated to 37ﾟC.The pipettes at each end of the arteriole were connected to water manometers, and the intraluminal pressure was set at 40 mmHg to match previously reported in vivo pressure. The arteriole was observed at x320 magnification, and its image was recorded using a video camera and displayd on a television monitor. Vessel diameters, wall thickness, inner and outer pressures, and wall tension were continuously mesurements with a video caliper amd microcomputor. Less