Interconnection between parameters of motor activity and blood glucose concentration in newborn rats at starvation and under glucose load conditions

The study is carried out on the one-, 3-, 5-, 7, and l0-day old free moving or loosely fixed rat pups (P1–10). In satiated and submitted to the 24-h starvation rat pups, parameters of spontaneous periodical motor activity (SPMA) and the blood glucose content were determined. The total glucose level in hungry rat pups was, on average, 1.5–2.5 times lower than in satiated animals. Administration of glucose to hungry rat pups increased 6–11 times its concentration in blood as compared with the animals not obtaining glucose. The glucose administration to the satiated rat pups led to a rise of its level in blood from 2 to 5 times as compared with intact animals, which was 2–3 times less than in the case of hungry animals. Analysis of pattern of motor activity recorded under conditions of the glucose deficit caused by the 24-h starvation of rat pups did not reveal significant changes of ratio of rhythmical components. Introduction of glucose to hungry and to the lesser degree to satiated rat pups led to potentiation of the minute rhythm of activity in all age groups. The exception was the first day after birth when the glucose administration to satiated rat pups promoted an enhancement of the decasecond rhythm and a decrease of the total level of motor activity. Comparison of ontogenetic dynamics of the SPMA parameters and the glucose content in blood of hungry rat pups revealed the clearly expressed regularity absent in the satiated animals: the glucose level in blood was higher during activity than in the state of rest. The performed study has shown that intensity, duration, and, to a degree, pattern of SPMA in the newborn rat pups depend on the level of satiety, and can be significantly changed in the artificially produced hypo- or hyperglycemia. The existing ontogenetic fluctuations in the character of reaction at performance of the glucose tolerance test can be connected both with morphofunctional maturation of the motor system and with immaturity of various chains of carbohydrate metabolism.