[The dynamic activity of the posterior roots of the thoracic spinal cord during ionic-osmotic stimulation of the liver]. / Dinamika aktivnosti zadnikh koreshkov grudnogo otdela spinnogo mozga pri ionoosmoticheskoi stimuliatsii pecheni.

Spontaneous rate of discharges of the T6-8 segments and their responses to ionic and osmotic stimuli resembled those of the individual receptor units of the liver. The data suggest that the hepatic intravasal, vasal-interstitial and interstitial volumoreceptors and "water" osmoreceptors have their afferent link in the spinal pathway.

[The dynamic activity of the hepatic interstitial volume receptors under conditions of varying stimulation]. / Dinamika aktivnosti interstitsial'nykh voliumoretseptorov pecheni v usloviiakh razlichnoi stimuliatsii.

The activity of single functional units with interstitial and vasal-interstitial patterns of discharge were studied in different kinds of stimulation: repeated infusions of saline with 10-min. intervals or continuous long-term infusions of hypertonic sodium chloride solutions into the portal vein, during and after acute block of hepatic venous outflow. The former infusions potentiated responses of these units. The long-term infusions of hypertonic NaCl solutions led to durable responses with a delayed onset and/or maximal manifestation. The data obtained suggests a major role of these receptors in the sodium balance control under normal and pathological conditions.

[Interstitial volume receptors of the liver]. / Interstitsial'nye voliumoretseptory pecheni.

The study of the impulse activity of single afferent hepatic fibers in depth has found out that there are volume-sensitive units reacting upon the short-time infusion of the different test solutions into the portal vein. But they are displaying complex dependence of the response's characteristics not only on the magnitude increasing in intraportal volume but also on "quality" of the infused substance and total quantity of the injected fluid. There are units both responding for infusion period and after it with the latencies from 10 s to 2-3 min. The second phase of these units responses was more pronounced than the first one. The response patterns of the studied units are convincing data on an interstitial localization of the one type volumereceptors and a vasal-interstitial localization of the others. The results suggest that the significant role in the control of the water-salt homeostasis is played by these receptors.

Participation of the liver receptors in the regulation of ion composition osmolality and extracellular fluid volume.

Characteristics of 106 fibres dissected from liver afferent nerves were examined on 52 cats anaesthetized with intravenous nembutal administration. The afferent discharge of these fibres has been recorded during intraportal infusions of the different test solutions (75, 300, 450 mM sodium chloride; 8, 10.7 mM potassium chloride in normal saline; 300, 600 mM glucose and mannitol in normal saline and water). The results of the experiments showed that hepatic afferent fibres differ from each other in the following: spontaneous discharge rate, response to different stimuli, threshold, and the adaptation rate. Various receptor units responded specifically to a change either in the intraportal volume, or the osmolality, or both to NaCl and KCl concentration in the portal circulation. These data suggest an existence in the liver of highly specific receptor's populations: mechano(volume)-, osmo-, Na+-sensitive and K+-sensitive one. These receptors can serve as an informative link in the regulation of the water-salt homeostasis.

[Character of liver mechanoreceptor spike activity after stopping blood flow through the hepatic veins]. / Kharakter impul'snoi aktivnosti mekhanoretseptorov pecheni pri prekrashchenii ottoka krovi iz pechenochnykh ven.

The spontaneous activity and responses of hepatic mechanoreceptors to an increase in the portal circulation volume were examined before and after the stopping of the outflow from hepatic veins in anesthetized cats. Most of spontaneously "silent" receptors responded with high frequency impulses immediately after the clamping of the hepatic veins. In the units with a low resting activity, there took place a gradual increase in discharge frequency and its peak was seen 2--6 minutes later. In the units with high initial activity, the impulsation disappeared completely 0.5--1 min after the stopping of the outflow. The responses to an increase in the portal circulation volume during the stopping of the outflow was absent in all the units. After removal of the venous clamp the activity of these units returned to the initial level and so did the responses to an increase in the portal circulation volume. An importance of afferent signalization of hepatic mechanoreceptors is discussed for water-salt homeostasis control in pathological conditions in which the normal venous outflow is deranged.

[Electrophysiologic characteristics and functional role of hepatic mechanoreceptors]. / Elektrofiziologicheskaia kharakteristika i funktsional'naia rol' mekhanoretseptorov pecheni.

In our previous studies, the liver was found to have different specific receptors: mechano(volume)- osmo-, Na+- and K+-sensitive ones. Here, the electrophysiological characteristics of the mechanoreceptors is presented: five types of receptors were distinguished according to their patterns of activity, as well as fast and slowly adapting ones--according to functional characteristics. The hepatic mechanoreceptors seem to participate in systemic regulation of the circulation through the organ (feed--back) and to be an important informative link of the volume--regulating reflex.

[Electrophysiological characteristics, nature and localization of the hepatic osmoreceptors]. / Elektrofiziologicheskaia kharakteristika, priroda i lokalizatsiia osmoretseptorov pecheni.

Functional characteristics of 45 osmosensitive units of the liver were analysed under conditions of intraportal administration of different osmotic stimuli. The most effective stimulus was the distilled water, the other substances, according to intensity of the response, were arranged in the following order: NaCl greater than glucose greater than or equal to mannitol. The latency of response varied from 1.5 to 10 sec, and the rate and duration of impulsation were dependent on tonicities of solutions. True osmoreceptors are supposed to exist in the liver tissue.

[Osmo-, iono- and volume receptors of the liver]. / Osmo-, iono- i ob''emnye retseptory pecheni.

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.