EFFECT OF ADDITION OF CALCIUM AND MAGNESIUM IN DRINKING WATER ON STATE OF CARDIOVASCULAR SYSTEM IN SPONTANEOUSHYPERTENSIVE RATS

The aim. To assess the effect of enrichment of calcium and  magnesium in drinking water on the level of arterial pressure (BP), myocardial remodeling processes, and  autorhythmic contractile activity of the  portal vein (PV) of spontaneously hypertensive SHR rats  and control WKY rats. Material and methods . One group of SHR rats  received drinking water enriched with calcium (120 mg/L)  and  magnesium (45 mg/L)  from a 6-week-old age within 2 months. Two other groups of SHR and  WKY rats  received St. Petersburg tap water with a low content of Са 2+ (8 mg/L) and Mg 2+ (3 mg/L). All groups received a standard diet. At the end of the observation period, rats  were assessed with blood pressure, myocardial mass index, urea level (UR), total cholesterol (Chol), total calcium (totalCa) and  albumin (Alb) in blood. A contractile activity of PV was investigated by the method of myography (in vitro). The total and maximal amplitude and frequency of contractions of PV, as well as the work done by PV was determined. Results. In SHR rats, the enrichment of drinking water of Са 2+ and Mg 2+ , prevented the progressive rise BP to the level characteristic of the SHR, resulting in its stabilization at 18% lower than in the SHR of the mineral deficient group. Theincreaseinthecontent of Са 2+ and  Mg 2+ in drinking water did not affect the degree of myocardial hypertrophy, as well as on the level of UR, totalCa and Alb of blood, but led to a decrease in the level of total cholesterol compared to animals that received low-mineralized water. The options of the autorhythmic contractile activity depended on the mineralization of drinking water. The addition of Са 2+ and  Mg 2+ to the drinking water of SHR rats  resulted in a decrease in both  the amplitude of contractions of PV and  the work performed by PV as compared with rats  of mineral deficient groups. Conclusion. The researches have  shown the important role of mineral composition of drinking water in processes of regulation of a level of arterial pressure. In spontaneously hypertensive SHR rats, the  antihypertensive effect of drinking water enrichment with Са 2+ and  Mg 2+ has  been revealed. The increase in the  intake of exogenous calcium and  magnesium with water modifies the autorhythmic contractile activity of the portal vein of spontaneously hypertensive SHR rats, normalizing it to a level characteristic of normotensive WKY rats.