Role of physical factors in the natriuresis induced by acetylcholine.
Role of physical factors in the natriuresis induced by acetylcholine.
复制标题
物理因素在乙酰胆碱诱导的尿钠排泄中的作用。
DOI：
10.1152/ajplegacy.1970.218.3.880
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发表时间：
1970
期刊：
影响因子：
--
通讯作者：
F. Epstein
中科院分区：
文献类型：
--
作者：
J. Hayslett;D. T. Domoto;M. Kashgarian;F. Epstein
METHODSMale Sprague-Dawley rats weighing ZOO-400 g were studied by micropuncture techniques. All animals had free access to regular Purina chow and tap water until the experiment. Anesthesia was induced with inactin (Promonta, Hamburg, Germany), loo-130 mg/kg, a tracheostomy was performed, the bladder was cannulated, and the right ureter was ligated and transected proximally to the tie. The left and right external jugular veins were cannulated for intravenous infusions. Mean arterial pressure was recorded with a catheter placed in the left carotid artery, using a mercury manometer. Intra-arterial infusions were given through a polyethylene catheter(PE-10) threaded into the aorta through the left femoral artery, with its tip placed at or slightly above the orifice of the left renal artery. The position of this catheter was confirmed at the termination of the experiment. The left kidney was exposed, its capsule stripped, and the kidney immobilized in a plastic cup for micropuncture as previously described (24). During surgery, isotonic saline equal to 1% of the body weight was infused intravenously to compensate for losses of extracellular fluid. Isotonic NaCl, 150 mEq/liter, containing either inulinmethoxy-3H or p-aminohippurate-3H was continuously infused intravenously during the experiment at a rate of 1.2 ml/hr. After a prime of 50 PC, the isotopes were infused at a rate of 50 &hr. During control periods, isotonic NaCl was delivered through the aortic catheter at 2.4 ml/hr, while in experimental periods acetylcholine was infused in a similar volume at a rate of 4.0 pg/min. At least 15-20 min were allowed for equilibration after starting the infusion of acetylcholine before beginning collections. There were usually two collections of urine of approximately 30 min each, made during both control and experimental periods. Samples of blood were taken from the tail before and after each collection. The radioactivity of samples in Bray’s solution was determined in a Tri-Carb liquid scintillation spectrometer. Counts were corrected for quenching by using a 3H internal standard. The concentration of sodium in serum and urine was determined on an internal standard flame photometer.The reabsorptive half-time (t& of isotonic saline in split-droplet microperfusions of single proximal and distal tubules was measured by sequence photomicrography as described by Gertz (9). Distal tubules were identified by the characteristic appearance of lissamine green after intravenous injection. The diameter of the oil column adjacent to the isolated droplet was used to estimate the diameter of the droplet. This dimension was measured in enlarged photographs and expressed in microns by comparison with a stage micrometer photographed at the same magnification. The time taken for fluid to pass through the first 55-60% of the proximal tubules (proximal transit time) was meas-
