The Intrarenal Pressure

Abstract

By the use of a new method for measuring the intrarenal pressure, we have shown it to be about 26 ram. Hg in deeerebrate dogs (1, 2). I t is the purpose of the present report to amplify this series and also to give data obtained on unanesthetized normal dogs and on dogs under sodium pentobarbital anesthesia. The relation between the intrarenal pressure and the age, weight, blood pressure, and sex of the dogs was also ascertained. A few measurements of the I R P in cats, rabbits, and rats will also be reported. MethodsThe intrarenal pressure is measured (2) by thrusting deep into the medulla of the kidney a perforated 20-gauge needle, which is connected with a manometer. 250 ram. Hg is then suddenly imposed on the system. The elasticity of the manometer, etc., rapidly forces a small amount (about 10 c. ram.) of saline-heparin into the kidney until equilibrium is reached with the pressure of fluids in the kidney tissue. The pressure changes are recorded; when no further change in pressure is registered, this is the objective measurement of intrarenal pressure (to be abbreviated henceforth as IRP).The IRP was measured three times in each dog, the mean of the three measurements being given in these data. Readings were taken immediately after the kidney was exposed with care to avoid manipulation of the kidney and trauma. Systolic and diastolic blood pressures were taken simultaneously by optical means with a glass Bourdon tube (3, 4), after cannulation of the femoral or carotid artery. Dogs 1 year old or over were used, the age being estimated from the teeth wear by Boeuish's (5) method. The decerebrated dogs were prepared as described by Fee (6); the IRP of these animals was taken after the animal had breathed off the ether employed during the surgical procedure, at a time when the animal's spinal reflexes had returned. In the experiments with unanesthetized dogs, explantation of the kidney to a subcutaneous position in the flank, with excision of the eontralateral kidney was accomplished, following in general the technic of Rhoads (7). About 15 days afterwards, observations of IRP were taken. With the kidney explanted, measurements of IRP were readily taken by thrusting the needle through the skin and into the kidney. The dogs were trained to lie still; they were neither hurt nor excited during the procedure.In order to determine whether different species of animals would have the same magnitude of IRP as dogs, measurements were also made on cats, rabbits, and rats. All were anesthetized with sodium pentobarbltal.

Experimenteller Beitrag zum Verhalten der Nieren bei akuter hypotoner Hyperhydration

“…(48,64), sowie G o t t s c h a l k (23,24) Es läßt sich während der Ausbildung der osmotischen Nephrose recht deutlich ein Anstieg des intrarenalen Druckes beobachten. Nach Dekapsulation tritt ein starker Druckabfall unter die Aus gangswerte auf, hingegen kam die Ausscheidung nicht wieder in Gang.…”