Regulation ranges and patterns of adaptation to hyponatremia by cells of various organs and tissues of vertebrate animals.

Background: The effect of hyponatremia on the body is studied on model objects. The related question concerns the degree of compliance between manifestations of hyponatremia and protective mechanisms in humans and other species of vertebrates.

Objectives: To identify the regulation ranges and patterns of adaptation to hyponatremia by cells of various organs and tissues of vertebrate animals.

Methods: To assess the regulation ranges and patterns of adaptation to hyponatremia, a comparative analysis has been applied to the data obtained from humans, mammals and freshwater fish.

Results: The physiological content of sodium in the blood plasma in humans is regulated and maintained within a narrow value range which is similar to that occurring in a number of other vertebrate species. The counteraction to hyponatremia is performed by means of accelerating the transport of sodium, potassium, chloride and organic osmolytes from the cells into the internal environment.

Conclusions: The data regarding mammals are fragmented and reflect the manifestation of protective mechanisms taking place during the initial period of hyponatremia. The method tested on freshwater fish allows for studying patterned changes in inorganic ions and content of organic osmolytes in the internal environment and cells of various organs and tissues of the body from the start of developing hyponatremia till the completion of the recovery process in vivo (Fig. 2, Ref. 72).