The aim of this study was to investigate the effect of combined deficiency of all
vitamins on the manifestation of unconditioned reflex and learning (in response to an electric current) in growing Wistar rats with initial
body weight 53.4 ± 1.2 g (45.5-62.0 g). 20 of 46 tested male rats (latent period of transition from the illuminated chamber to the dark compartment did not exceed 60 s) were included in the experiment. Rats were randomly divided into 2 groups (control and experimental) for the duration of the latent period and body mass. Within 23 days the rats of the control group received a complete semisynthetic diet. Combined
vitamin deficiency in tested rats was caused by 5-fold diet decrease of the amount of
vitamin mixture without
vitamin E. On the 12th day the second phase of testing was performed, during which the rat received electrocutaneous irritation on paws (current 0.4 mA, 8 seconds) after transition to the dark compartment of the chamber. Preservation of the conducted reflex was performed 24 h and 9 days after training. On the 23rd day pre-anesthetized with
ether rats were taken out from the experiment by
decapitation. The content of
vitamin A (
retinol and
retinol palmitate) and E (
tocopherols) in plasma and liver and in the
sunflower oil was analyzed by HPLC, the level of
vitamins B1 and B2 in liver and
casein by fluorimetric method, blood serum
malondialdehyde content--by spectrophotometric method. Reducing of
vitamin mixture amount of the diet lead to significant reduction in liver
vitamin A, E, B1, and B2 level and in blood plasma
vitamin A and E concentration by the end of the experiment, but had no effect on blood plasma MDA concentration. On the 12th day of
vitamin deficiency in rats manifestation of unconditioned reflex (
photophobia) has been deteriorated, as evidenced by the significant 3,2-fold increase of latent period of transition to the dark compartment compared with animals fed a complete diet (47.8 ± 15.8 vs 14.8 ± 3.6 sec), but their ability to learn hadn't been effected. Based on the data that
vitamin deficiency, especially of
vitamin-
antioxidants, causes oxidative stress, and that increase of
corticosterone level in hippocampus during aging significantly inhibits the function of the brain, we can assume that increasing of
corticosterone level may be one of the cause of the detected
cognitive impairment, as isolated
vitamin A deficiency in rats increases tissue
corticosterone levels.