Pulmonary vascular carbonic anhydrase activity.
Pulmonary vascular carbonic anhydrase activity.
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肺血管碳酸酐酶活性。
DOI：
10.1152/jappl.1983.55.1.75
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发表时间：
1983
期刊：
影响因子：
--
通讯作者：
Crandall,ED
中科院分区：
文献类型：
--
作者：
Bidani,A;Mathew,SJ;Crandall,ED
材料和方法分离的肺制剂。雄性SD大鼠(体重250~350g)用戊巴比妥钠(50 mg/kg)ip麻醉。进行气管切开术，并用室内空气对肺进行机械通风(型号680型，哈佛仪器，马萨诸塞州米利斯)。肺部会不时地发出叹息声。切开腹部和胸部，横断心脏双侧脑室，经右室向肺动脉插入插管。然后，通过肺动脉插管以20ml/min的速度(7014泵，Cole Parmer，芝加哥，IL)注入PRB溶液(37℃)，迅速清除肺循环中的血液。将肺从胸腔中取出，在左心房放置一个插管，在37℃时将肺悬挂在一个水套的房间里。左心房插管连接到T管，T管的一只手臂与大气开放。T管的第三臂连接到停流pH电极，如前所述(7)。肺悬吊后，将灌流液切换成PRB液，预泡含20%Oz-3-10%C02-Balance N的混合气体。灌流液没有再循环。实验装置的原理图已在前面报告过(7)。灌注液的制备。PRB溶液中含有0.65CaC12、1.2MgSOd、4.7KCl、16.67Na2HP04和3.33KH，PO*。当用5%的COZ、20%的02和75%的氮的混合气体预泡时，灌流液也含有24.9 mM的NaHC03和88.9 mM的氯化钠。用10%COZ、20%02和70%N预泡时，溶液中含有36.5mM NaHC03和80.3mMNaC l；用3%CoG、20%02和77%N预泡时，溶液中含有12.5mM NaHC03和104.3 mMNaC l。此外，灌流液C含有0.08 mM的乙酰唑胺(ACTZ)。灌流物B含有不同量的Actz(~0，co.08毫米)。灌流液A不含ACTZ。一个典型的实验进行如下。肺通气量为2ml，呼吸频率为60次/min，灌流液A为20ml/min，直至达到稳定状态。在此后的给定时间，灌流液以15毫升/分钟的速度通过停流电极装置排出，以确保一定的流量始终从T管的开放臂继续流出。在25-30毫升的灌流液被取出后，流经电极装置的流量突然终止。监测停流前后电极室中灌流液的温度和pH值，记录在存储示波器屏幕(5103N，Tektronix，Beverton，OR)上，并拍照。灌流液从肺到电极装置的传递时间约为6 S。直到t 0.0005可测量到pH的变化和温度的变化
MATERIALS AND METHODSIsolated lung preparations. Male Sprague-Dawley rats (250-350 g body wt) were anesthetized with pentobarbital sodium (50 mg/kg ip). A tracheostomy was performed, and the lungs were mechanically ventilated (model 680, Harvard Apparatus, Millis, MA) with room air. The lungs were periodically sighed. The abdomen and chest were opened, both ventricles of the heart were transected, and a cannula was inserted into the pulmonary artery through the right ventricle. Blood was then rapidly cleared from the pulmonary circulation by infusing a PRB solution (37 C) at 20 ml/min (pump model 7014, Cole Parmer, Chicago, IL) through the pulmonary artery cannula. The lungs were removed from the thoracic cavity, a cannula placed in the left atrium, and the lungs hung in a water-jacketed chamber at 37 C. The left atria1 cannula was connected to a T tube, one arm of which was open to the atmosphere. The third arm of the T tube was connected to a stop-flow pH electrode which has been described previously (7). After the lung was hung, perfusate was switched to a PRB solution which had been prebubbled with gas mixtures containing 20% Oz-3-10% C02-balance N,. Perfusate was not recirculated. A schematic diagram of the experimental apparatus has been reported previously (7). Preparation ofperfusion fluids. The PRB solution contained (in mM): 0.65 CaC12, 1.2 MgSOd, 4.7 KCl, 16.67 Na2HP04, and 3.33 KH, PO*. The perfusate also contained 24.9 mM NaHC03 and 88.9 mM NaCl when prebubbled with a gas mixture consisting of 5% COZ, 20% 02, and 75% N2. The solution contained 36.5 mM NaHC03 and 80.3 mM NaCl when prebubbled with 10% COZ, 20% 02, and 70% N,; and 12.5 mM NaHC03 and 104.3 mM NaCl when prebubbled with 3% Cog, 20% 02, and 77% N,. Perfusate C, in addition, contained 0.08 mM acetazolamide (ACTZ). Perfusates B contained variable amounts of ACTZ (~ 0, co. 08 mM). Perfusate A contained no ACTZ.Experimental procedure. A typical experiment proceeded as follows. The lung was ventilated (stroke volume= 2 ml, frequency= 60 breaths/min) and perfused (20 ml/min) with perfusate A until a steady state was attained. At a given time thereafter, perfusate was withdrawn through the stop-flow electrode apparatus at 15 ml/min, making certain that some flow always continued to exit from the open arm of the T tube. After 25-30 ml of the perfusate had been withdrawn, flow through the electrode apparatus was suddenly terminated. Temperature and pH of the perfusate in the electrode chamber were monitored before and after stopping flow, recorded on a storage oscilloscope screen (5103 N, Tektronix, Beaverton, OR), and photographed. The transit time for flow of the perfusate from the lung to the electrode apparatus was approximately 6 s. Changes in pH were measurable up to t 0.0005 and changes in temperature