Transvascular fluid shifts following single injections of catecholamines in the alert rat: comparison of the effects of adrenalin, noradrenalin and stimulated activity

Abstract

Single injections of noradenaline and adrenalineeeee were made into the v. cava of conscious rats during continuous registration of arterial blood pressure and conductivity (reciprocal hematocrit) in blood from different circulatory areas. The resulting hct and B.P. changes were compared with similar changes elicited by a 3-sec tactile stimulus. Two phases of hct response--the first due to local vascular reactions, the second due to a general vasodilatory reaction--can be distinguished. Whereas adrenalin and noradrenaline show differential effectivity in producing the local reactions (the former more potent as a precapillary vasoconstrictor, promoting hct drop due to fluid inflow in the portal and hepatic vein, the latter more so in the renal vein and the aorta), adrenalin is invariably more effective in producing the second phase dilatory reaction with fluid outflow (hct rise). In the v. cava close to the iliac bifurcation a greater hemoconcentrative potency of adrenalin can be demonstrated, but only by close injections into the aorta. Close injections into the portal vein make postcapillary hepatic reactions more sensitive to adrenalin manifest. The catecholamine dose equivalent to a 3-sec tactile stimulus in the rat is 80-120 ng.

Continuous simultaneous measurement of plasma protein concentration and hematocrit in the alert rat. A short preliminary report

“…As mentioned, the method was developed in order to substantiate the results of experiments in which very rapid transvascular fluid movements were demonstrated essentially by blood conductometry (3,4,5). For the most part this has successfully been done qualitatively in the present experiments.…”

“…In previous papers (3,4,5), conductometrically measured hematocrit (hct) was monitored as an indicator of fluid content of blood flowing in various parts of the circulatory system of the rat. The assumption of a correlation between hct changes and transvascular fluid movements was substantiated by occasional determination of both hct and total plasma protein in situations where sufficiently large and sustained changes took place for reliable measurements.…”

Venous pressures in the alert rat: effects of activity and single injections of catecholamines

“…Surgical and experimental procedures were described in detail in previous papers (2,3,4). Nonobstructive vascular catheters of 0.5 mm inner diameter and 17 cm *) Supported by DFG-Grant AZ 3/3 length were implanted in various combinations (see results) in the following vessels: V. cava proximal to and V. cava distal to the renal veins, aorta abdominalis, V. portae, a branch of the V. mesenterica superior.…”

“…In two previous papers (3,4), transvascular fluid-shift transients in several circulatory areas of the alert rat following short activity periods and single injections of catecholamines were described. In the face of the profound influences on capillary filtration rates it has (1), venous pressure should be an essential parameter to be measured for a better assessment of the underlying mechanisms.…”