STUDY FOR THE BEHAVIOR, MNESTIC REACTIONS, AND PAIN SENSITIVITY OF FEMALE RATS IN THE SETTING OF AN EXPERIMENTAL MAGNESIUM DEFICIT

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It is well known that magnesium is an important regulator of body's vital functions. Magnesium deficiency is observed in many physiological and pathological conditions (unbalanced diet, diabetes, CVD etc). Magnesium ions are important in the implementation of immune responses, in inflammation, in nerve and muscle irritability. Purpose of the study was to investigate the effect of experimentally established nutritional magnesium deficiency on behavioral activity, mnestic reaction and pain sensitivity of female rats. Materials and methods of study: the experiments were performed using 20 outbred female rats 3-3.5 months old with initial weight of 250-254 g. Female rats were divided for the experiments into 2 equal groups of control and experience. The control group was on a full diet with magnesium oxide at the rate of 500 mg/kg of a diet. Experimental group followed a diet without additional magnesium salts with non-magnesium polymineral mixture AIN-76 (USA) during 8 weeks, the diet was kneaded in deionized water. The rate magnesium deficiency development was controlled by the level of magnesium in plasma and red blood cells by the method of V.V. Menshikov [1987]. Behavioral activity in rats was studied in the "open field" test, mnestic reaction was studied in the test "CPAR". Pain sensitivity was evaluated in a "hot plate" test (method of I. Kitchen, M. Crowder, [1985]). Statistical processing was done in Microsoft Excel and Statistica 6.0 programs. Results: according to the results of the trials on animals kept on a diet without magnesium salts, revealed a gradual deterioration in their general condition, the presence of general dystrophic changes (fading and loss of fur, flushing of exposed skin, weight loss), which may indicate the development of magnesium deficiency in the body. At the end of the 8th week course of prescribed diet, blood plasma from experienced females showed the reduction of the magnesium concentration by 28.62% (p<0.05) and by 18.01% (p<0.05) in red blood cells. According to the results of an "open field" test, these rats showed a significant increase in horizontal, vertical and mink activities (by 50% 64% in average) but a decrease of emotionality (71.7% p <0.05). The "CPAR" test revealed significant increase in the sensitivity and vocalizations during training (31% and 24.0% respectively) and reduced latency of entering the dark chamber. When reproducing the skill experienced female rats latent period of its first entry into the dark "dangerous" chamber increased by 11.4% (p˃0.05) and the time spent there decreased by 24% (p <0.01), while the number of visits did not change in relation to the control values. In the "hot plate" test the female rats with hypomagnesaemia showed a distinct shortening of the latent period of hind paws licking by 35.6% (p <0.01), which may indicate the increase of their pain sensitivity. Conclusions: thus, according to the results of the studies the experimentally created model of an alimentary hypomagnesaemia female rats have deteriorating general condition, increased motor behavior and sensitivity to pain, which can be used for testing and evaluating the effectiveness of pharmacological correction of magnesium-bearing drugs.