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.