HYDROSTATIC PRESSURES IN PERTIBULAR CAPILLARIES AND TUBULES IN RAT KIDNEY
HYDROSTATIC PRESSURES IN PERTIBULAR CAPILLARIES AND TUBULES IN RAT KIDNEY
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DOI：
10.1152/ajplegacy.1971.220.5.1422
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发表时间：
1971-01-01
影响因子：
--
通讯作者：
BERLINER, RW
中科院分区：
文献类型：
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作者：
FALCHUK, KH;BERLINER, RW
方法选用SD雄性大鼠，体重ZOO ~ 300 g。允许它们自由饮水，但在研究前14-16小时不进食。通过腹膜内注射Inactin（100 mg/kg）麻醉每只大鼠。将动物置于温度调节的显微穿刺台上，并进行气管造口术。将留置聚乙烯导管（编号50）插入右颈静脉以输注丽丝胺绿色，插入左颈静脉以输注液体，并插入左股动脉以估计血压。通过左肋下切口暴露左肾，并将其与左肾上腺和肾周脂肪轻轻分离。将肾脏悬于Lucite保持器上，并用石英棒照射其表面。用加热到37 ℃的等渗盐水浸泡肾脏。将流向肾脏的生理盐水维持在最低水平，以确保表面保持湿润。调整肾脏保持器，以便大部分液体在不进入动物腹腔的情况下流出。除非特别说明，否则在每种情况下，肾包膜都保持完整，并注意不要拉伸肾血管。根据Wiederhielm等人描述的类似设备的计划，使用固态电子器件构建伺服压力测量系统。（十四）、该系统使用装有1.5 M NaCl的微量移液管作为惠斯通电桥的臂。在刺穿小管或血管之前，在移液管尖端的1.5 M NaCl和等渗盐水之间形成界面。这是通过将移液器尖端浸入覆盖肾脏表面的盐水层中来实现的。移液器阻力的有效分量是从吸头到界面的等渗盐水柱长度的函数。在几个移液管中，该电阻范围为300至600千欧。当移液器的阻力与电桥平衡并形成稳定的界面时，移液器即可使用。移液管进入小管或容器将导致界面由于小管或容器中的压力而进一步移动到移液管中。这导致移液管的阻力增加。电阻的这种增加被传感装置检测为电桥的不平衡。来自传感装置的输出信号与移液器的电阻变化成比例，并用作传感器的反馈信息。该传感器由扬声器和波纹管组成，并以液压方式连接到微量移液器和压力传感器（图1）。传感器将液体从移液器中排出，直到移液器阻力再次平衡电桥。应该注意的是，当移液器的阻力恢复时，电桥平衡恢复，而不一定是当流体界面返回到最初建立平衡的位置时。如果正在测量压力的流体的电导率与进行控制平衡时的电导率不同，则恢复电桥平衡所需的界面将不同。然而，只有当传感器压力等于移液器尖端处的压力时，才能稳定地建立平衡。保持桥平衡所需的压力是预先确定的。
METHODSMale Sprague-Dawley rats weighing ZOO-300 g were used. They were allowed free access to water, but were deprived of food for 14-16 hr prior to study. Each rat was anesthetized with an intraperitoneal injection of Inactin (100 mg/kg). Th e animal was placed on a temperatureregulated micropuncture table and a tracheostomy was performed. Indwelling polyethylene catheters (no. 50) were inserted into the right jugular vein for infusion of lissamine green, into the left jugular vein for infusion of fluids, and into the left femoral artery for estimation of blood pressure. The left kidney was exposed by a left subcostal incision and gently separated from the left adrenal gland and perirenal fat. The kidney was suspended on a Lucite holder and its surface was illuminated by a quartz rod. The kidney was bathed with isotonic saline heated to 37 C. The flow of saline onto the kidney was maintained at a minimal level to insure that the surface remained moist. The kidney holder was adjusted so that most of the fluid ran off without entering the animal’s abdominal cavity. The renal capsule was left intact in each case, unless specifically stated, and care was taken that the renal vessels were not stretched.A servo pressure-measuring system was constructed, using solid-state electronics, from the plans described for a similar device by Wiederhielm et al.(14). The system utilizes a micropipet filled with 1.5 M NaCl as an arm of a Wheatstone bridge. Prior to puncture of a tubule or vessel, an interface is formed between the 1.5 M NaCl at the tip of the pipet and isotonic saline. This is accomplished by immersing the pipet tip into a layer of saline covering the kidney surface. The effective component of the pipet resistance is a function of the length of the column of isotonic saline contained from the tip to the interface. In several pipets this resistance ranged from 300 to 600 kilohms. When the resistance of the pipet balances the bridge and a stable interface is formed, the pipet is ready for use. Entry of the pipet into a tubule or vessel will cause movement of the interface further into the pipet as a consequence of the pressure in the tubule or vessel. This results in an increase in the resistance of the pipet. This increase in resistance is detected by a sensing device as an imbalance of the bridge. The output signal from the sensing device is proportional to the change in resistance of the pipet and serves as a feedback message to a transducer. The transducer consists of a loudspeaker and a bellows and is connected hydraulically to the micropipet and to a pressure transducer (Fig. 1). The transducer drives fluid out of the pipet until the pipet resistance once again balances the bridge. It should be noted that the bridge balance is restored when the resistance of the pipet is restored, not necessarily when the fluid interface is returned to the position at which the balance was originally established. If the fluid whose pressure is being measured has a conductivity different from that in which the control balancing was done, the interface required for restoring bridge balance will be different. However, balance can be stably established only when the transducer pressure is equal to that at the pipet tip. The pressure required to maintain the bridge balanced is pre-