[Role of vasopressin and aldosterone in the mechanism of osmoregulating reaction].

Possible mechanisms responsible for a natriuretic response to NaCl hypertonic solution (515 mmol/l) digestively administered were studied in chronic experiments on Wistar and Brattleboro rats with continuously implanted urinary bladder catheters. The administration of the solution resulted in rapid antidiuresis and marked natriuresis though the plasma levels of N+ remained unchanged throughout the experiment. Natriuresis did not differ in the Brattleboro and Wistar rats.

[Osmotic and ion-regulatory responses in chronic diffuse liver pathology].

Patients with chronic hepatitis were found to develop an inadequate di- and natriuretic responses to osmotic agents administered into the gastrointestinal tract. In liver cirrhosis, the intensity of adaptive responses decreases or they completely disappeared. The causes for these abnormalities are impairment of osmoregulatory reflex links and dyscoordination of humoral factors.

[Changes in renal kaliuretic function in the dynamics of hepatic cirrhotic transformation].

During formation of hepatic cirrhosis in animals, excessive potassium loss has been found to depend on the increased loading of a nephron by its cation at its early stage and on abnormally changed tubular processes at late stages.

[Water-electrolyte balance in patients with cerebral arachnoiditis].

The paper discusses the results of studying the water-electrolyte exchange in patients with cerebral arachnoiditis. Basically new evidence has been obtained for the mechanisms of interaction of the liquor-circulating and osmoregulating systems of the body. There is a more intensive excretion of sodium and H2O during load sodium and water tests and a decrease in antidiuretic effects on hyperosmotic exposures in patients than in healthy individuals.

[Mechanism of changes in renal functions in osmotic irritation of the right atrium].

Chronic experiments conducted on 17 dogs whose ureters were brought out on the skin of the abdomen showed that administration of solutions of saccharose (1150 mmol/l) and NaCl (515 mmol/l) into the right atrium reduces diuresis and increases natriuresis. The concentration of atrial natriuretic factor in the blood does not change, vasopressin and cortisol secretion increases while that of aldosterone decreases. It is concluded that, in addition to the cardiopeptide mechanism regulating the blood volume, the right atrium possesses a reflex osmoregulatory mechanism.

[Effect of vasopressin, aldosterone and angiotensin on the permeability of the choroid plexus to water].

In anesthetized dogs with cannulae implanted in the lateral cerebral ventricle, the water transfer from the CSF to the blood was studied using determination of drainage of tritiated water injected into the ventricle. Vasopressin and aldosterone accelerated the transfer of tritiated water into veins whereas angiotensin decelerated it. The data obtained suggest that the above hormones regulate volume and osmolality of the CSF.

[Histochemical analysis of the glycosaminoglycan content in the choroid plexus during hydration and dehydration].

Histochemical study of the choroid plexus of the control and hydrated dogs injected with pituitrin solution (25 IU/kg bw) into the cerebral ventricle via a special cannula has demonstrated the ventricular surface of the choroid epithelium to bear compounds belonging to the class of glycosaminoglycans (GAG), primarily containing hyaluronic acid. The animals exposed to hydration showed an overt increase, whereas those treated with pituitrin a reduction in the content of GAG as compared with controls. The data obtained suggest that GAG contained by the choroid plexus are involved in the mechanism by which the rate of CSF formation is regulated.

[Role of vasopressin in regulating the volume and ionic composition of cerebrospinal fluid].

In chronic experiments on dogs with cannulae implanted in the lateral cerebral ventricle and occipital cistern, the CSF volume and Na+, K+ concentrations were measured during osmoregulating reaction and pituitrin infusion in the lateral ventricle. Isoosmotic CSF volume decrease in both experimental groups indicates that water-salt regulation in the body and brain tissues is performed by means of common neuro-humoral mechanisms with vasopressin participation.

[Reflex regulation of potassium excretion in the postnatal ontogeny of the dog].

In experiments on puppies ageing from 7 days to 8 months, as well as on adult dogs, studies have been made on reflex mechanisms of potassium excretion after injection of 135 mM KCl solution (0.7 ml/kg) to the portal vein. It was found that reflex regulation of potassium extrusion undergoes 3 developmental stages: in puppies up to 1 month potassium excretion is absent; from 1 to 4 months ionuresis is not differentiated, since injection of KCl increases excretion of both K and Na; after 4 months of postnatal life potassium excretion attains its final form.

[Afferent and central mechanisms of the osmoregulating reflex from the liver following hypothalamic deafferentation].

In anesthetized cats, 52 units of the hypothalamic supraoptic nuclei out of 65 retained the ability to respond to the osmotic stimulation after dissection of the brain stem (cerveau isolé). Administration of 1.0 ml 5% NaCl solution into the v.

[Osmo-, iono- and volume receptors of the liver].

by dissecting very fine strands of the liver afferent nerves, in cats, it has been possible to record activity of single fibers during intraportal infusion of different test-solutions. Different fibers were found which responded specifically to increase in the intraportal volume, to change of the osmosis and of concentration of ions. The liver was found to have highly selective specific populations of receptors: mechano (volume)-, osmo-, Na+-sensitive and K+ sensitive receptors.

[Reflex mechanism for maintaining magnesium homeostasis].

Local stimulation of the liver with MgC12 solution in unanesthetized dogs evoked a reflex magnesiuretic response by changing the tubular processes in the kidneys. The presence of selectively magnesium-sensitive receptors in the liver is supposed. The information from these receptors was shown to spread along the vagus nerves.

[Natriuretic component of the osmoregulating reflex during postnatal dog ontogenesis].

In experiments on puppies ageing from 3 days up to 8 months, as well as on adult dogs, studies have been made of mechanisms of excretion of water and sodium during the increase of osmotic concentration in the blood circulation of the liver and spleen. It was found that in contrast to adult dogs, in which the osmotic shift decreases diuresis and increases sodium excretion, the decrease of diuresis in 1-month puppies is accompanied by a decrease of sodium excretion. Two-component osmoregulatory reaction is developed only to the 2nd month of life.

[Osmo- and ionic liver receptors].

Role of the liver receptors in osmo- and ionic homeostasis regulation was studied in unanesthetized dogs. The presence of selective sodium-and potassium-sensitive receptors was shown in the liver receptor field. Stimulation of the ionic receptors evokes ADH-induced antidiuretic and specific ionuretic renal response.