Effect of CO2 and pH on bronchoconstriction caused by serotonin vs. acetylcholine.
Effect of CO2 and pH on bronchoconstriction caused by serotonin vs. acetylcholine.
复制标题
CO2 和 pH 对血清素与乙酰胆碱引起的支气管收缩的影响。
DOI：
10.1152/jappl.1972.32.1.39
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发表时间：
1972
影响因子：
3.3
通讯作者：
J. Nadel
中科院分区：
文献类型：
--
作者：
G. Sterling;P. Holst;J. Nadel
METHODSAnesthetized dogs. Sixteen dogs (9-20 kg) were anesthetized with chloralose(50 mg/kg, iv) and urethan (500 mg/kg, iv), paralyzed with succinylcholine administered intravenously, and ventilated with a Harvard respiratory pump after insertion of a tracheostomy tube. A catheter was inserted in the femoral vein for administration of drugs. Another catheter was inserted in the femoral artery; blood samples were collected from this artery at intervals during each experiment and were analyzed for pH and PCO~ with glass electrodes (Radiometer Ltd) and for PO:! with a Clark polarographic electrode. Expired CO2 concentration was monitored continuously with an infrared analyzer (Beckman LBl), and the rate and stroke volume of the respiratory pump were adjusted to maintain end-expired PCOZ between 25 and 40 mm Hg when the dogs were ventilated with room air. To measure transpulmonary pressure, we introduced a no. 10 Malecot catheter into the pleural space. We connected the catheter to one side of a differential pressure transducer(Statham, PM1 3 1); the other side of the transducer was connected to a side tap on the tracheostomy tube. A pneumotachograph(Fleisch, no. 1) and differential pressure transducer(Statham, PM5TC= t 0.5) were used to measure airflow. The output of the pneumotachograph was integrated electrically to obtain a volume signal. Total pulmonary resistance (RL) was measured by a subtraction method (6). The resistive pressure drop, airflow, expired CO:! concentration, and arterial blood pressure were recorded continuously(Electronics for Medicine, DR 12 recorder). Vector loops of resistive pressure against airflow were recorded intermittently from an XY oscilloscope and were observed continuously to check that the signal for elastic pressure was being subtracted correctly from total transpulmonary pressure.At the start of each experiment both cervical vagus nerves were cut, and the distal portions were placed on bipolar silver electrodes for electrical stimulation with square-wave pulses (intensity, 8-20 v; frequency, 15-30 pulses/set; duration, 3 msec) from a Grass, model S4DR stimulator. In each series, we compared measurements of RL obtained immediately before and at the end of 10 set of vagal stimulation. The measurements of RL were made with the dogs ventilated first with room air then with 10% CO2 in air and finally with room air again. After each change of ventilating gas mixture, we allowed 3 min for equilibration before making further measurements of RL. The mean of the two values during ventilation with room air was com-
