[Autonomic nervous control of plasma renin activity].
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Biomedical subjects
N Nachev
Publications and source records attributed to N Nachev.
[New method for the quantitative determination of antidiuretic hormone in the plasma].
Having in mind that ADH affects reapsorption of osmoticaly free water the authors examined urine diuresis together with its osmolality in 85 recipient rats. The animals endured water loading of 5% of their body weight by means of stomach lavages twice at 45 minutes intervals for a period of 3 days. Vena jugularis was cannulated under narcosis with heparinized polyethylene catheter, which was attached to the skull by means of a special socle. The training water loading continued two more days, after which AD activity or a standard solution of ADH was tested. Urine was collected every 15 minutes for a period of 120 minutes and its volume and osmolatily was determined. 0.2 ml of saline, standard or plasma, prepared for removal of nonspecific antidiuretic activity was administered on the 30th minute of the second water loading. There was a linear dependence between osmolality of urine and the administered amount of ADH. A standard curve of the ratio osmolality/microunits of ADH was prepared. The values of osmolality, obtained during administration of plasma were compared with those of the standard curve and the amount of ADH was determined in microunits. The method assures quantitative determination of ADH in values pover 10 microunits, which are obtained in animals after experimental affects and in some diseases of persons.
Animals↗
[Excretory function of the kidney after denervation and the administration of a beta-blockader].
Osmotic diuresis (15% mannitol, 4.5 ml/hr) was in duced in anesthetized rats. At the end of each of 10 consecutive 10-min clearance periods the following parameters were determined: diuresis, sodium, chlorine and osmotic excretion, GFR (inulin clearance). The animals were divided into three groups: a) controls, b) with bilateral renal denervation (performed one week earlier) and c) with application of beta-adrenergic blocking agent propranolol (Obsidan, Germed DDR) introduced intravenously 0.1 mg/100 g initially and 0.12 mg/100 g sustaining dose during 2 hrs. The experimental results showed an increased sodium excretion in denervated and obsidan--treated animals with no change of the total excreted osmotically active substances. In denervated animals the chlorine excretion was increased as well. The data suggest that, in osmotic diuresis, the renal denervation and beta-adrenergic blocking agents inhibit the tubular sodium transport. The kidney osmoregulatory functions remains unchanged.
Adrenergic beta-Antagonists↗
[Plasma renin and erythropoietic activity following a decrease in extracellular volume].
A reduction of the extracellular volume of the peritoneal dialysis in rats induced modifications in plasma renin activity, plasma erythropoietic activity, and in renin activity in the renal cortex. A significant increase in the renin and erythropoietic activity was revealed in the experimental animals. It is assumed that renin and erythropoietin could be regarded as two links of the same broad control system, responsible for optimum tissue oxygen supply.
Animals↗
[Changes in kidney function and the cortisol and ADH levels after peritoneal dialysis with 5% glucose in dogs].
The authors made peritoneal dialisis with 5% of glucose (7 ml/kg of body weight) in 11 dogs under the conditions of an acute experiments. They examined cortiosl and ADH activity, hematocrite and plasma protein in the samples of blood, obtained on the 20th and 50th minute. ADH was titrated biologicaly by a new method, proposed by Nacev. The results were compared with the changes in the circulatory and renal indices, obtained at the same procedure in the preceding investigations. There was an increase in the cortisol and ADH activity, which could be explained by the total hypovolemia, induced by peritoneal dialisis. The increase of the cortisol level is described as a separate link in a more complex mechanism, assuring metabolic homeostasis.
Animals↗