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).

Volume regulation of muscle cells in the carp Cyprinus carpio in response to hypernatremia.

BACKGROUND: Hypernatremia supports the movement of water from the intracellular to the intercellular space. This shift leads to cells shrinkage and disruption of intracellular processes, representing risk factors of morbidity and mortality in clinical circumstances. On the other hand, hypernatremia triggers protective mechanisms that counteract damage of cells. OBJECTIVES: To determine in experiments in vivo the ranges of sodium content regulation in the blood plasma of carp characterizing the norm and hypernatremia. To identify the patterns volume regulation of skeletal muscles cells in response to hypernatremia. METHODS: Carps were acclimating for 3 weeks to a different salinity in the range of 0-12 g/L. In the plasma and muscle tissue the concentration of sodium, potassium, calcium and magnesium was determined by the method of flame spectrophotometry. Water content in the muscles has been additionally determined. RESULTS: Carps acclimated in the salinity range of 0-6 g/L, maintained the concentration of sodium in blood plasma within of the range of 129-135 mmol/L (normonatremia). In the salinity zone of 6-12 g/L concentration of sodium in the blood plasma of fish has increased to 207 mmol/L (hypernatremia). Hypernatremia was causing the increase of the sodium, potassium, calcium and magnesium content in carp muscles and the drop of water level. CONCLUSIONS: Muscle tissue of carp adapts to hypernatremia by means of increasing inorganic ions by 70.8 % and organic osmolytes by 29.2 % (Fig. 2, Ref. 51).

Mercury in soil, earthworms and organs of voles Myodes glareolus and shrew Sorex araneus in the vicinity of an industrial complex in Northwest Russia (Cherepovets).

The characteristic properties of uptake and distribution of mercury in terrestrial ecosystems have received much lesser attention compared to aquatic particularly in Russia. Terrestrial ecosystems adjacent to large industrial manufactures-potential sources of mercury inflow into the environment frequently remain unstudied. This is the first report on mercury (Hg) levels in the basic elements of terrestrial ecosystems situated close to a large metallurgical complex.Mean values of mercury concentration (mg Hg/kg dry weight) in the vicinity of city of Cherepovets were the following: 0.056 ± 0.033-in the humus layer of soil; 0.556 ± 0.159-in earthworms; in the organs of voles Myodes glareolus (kidneys-0.021 ± 0.001; liver-0.014 ± 0.003; muscle-0.014 ± 0.001; brain-0.008 ± 0.002); in the organs of shrew Sorex araneus (kidneys-0.191 ± 0.016; liver-0.124 ± 0.011; muscle-0.108 ± 0.009; brain-0.065 ± 0.000). Correlation dependences between Hg content in soil and earthworms (r s  = 0.85, p < 0.01) as well as soil and all studied shrews' organs (rs = 0.44-0.58; p ≤ 0.01) were found.The results obtained evidence for a strong trophic link in the bioaccumulation of Hg in terrestrial food webs. Despite the vicinity to a large metallurgical complex, mercury content in the studied objects was significantly lower than values of corresponding parameters in the soils and biota from industrial (polluted) areas of Great Britain, the USA, and China.

Mercury Content in Organs and Tissues of Indigenous (Vulpes vulpes L.) and Invasive (Nyctereutes procyonoides Gray.) Species of Canids from Areas Near Cherepovets (North-Western Industrial Region, Russia).

Trophic and spatial components of ecological niches of two canids native Vulpes vulpes and introduced Nyctereutes procyonoides are overlapping partially in the studied region. Maximum concentrations of mercury in predatory mammals of Canidae family from surroundings of Cherepovets have been determined in liver and kidneys (over 0.50 mg/kg wet weight), with minimal concentrations in brain (<0.2 mg/kg wet weight). The amount of mercury in the same organs of the red fox and raccoon dog is not significantly different. These levels of mercury content are noticeably higher than those in the predators of Canidae family that inhabit territories of Europe lacking the local sources of mercury. At the same time, absolute values of metal quantity are commensurable with the levels registered in predators from the mercury polluted regions of Spain and Poland.