A -Study Design, B -Data Collection, C -Statistical analysis, D -Data interpretation, E -Manuscript Preparation, F -Literature Search, G -Funds CollectionBackground. the consumption of energy drinks (ed) is popular among young people. there are concerns that it could be harmful for their health. Objectives. the aim of the study was to analyze the influence of ed consumption on animals for 30 subsequent days on memory, weight gain and biochemical parameters (alanine transaminase-aLt, asparagine transaminase-ast, creatinine, cholesterol and glycated hemoglobin-Hba 1c ). Material and methods. the study was conducted on 32 mice (16 females and 16 males). the mice received standard feed for rodents ad libitum. the animals were randomly assigned to four groups (8 animals each): i -female controls provided with water ad libitum, ii -females provided with ED ad libitum, iii -male controls provided with water, and iV -males provided with ed. every 7 days memory retention in a passive avoidance task, and fresh spatial memory in a Y-maze were checked. the results were analyzed with statistica 10.0. p < 0.05 was considered statistically significant. Results. the consumption of ed did not affect fresh spatial memory or memory retention in the experiment. Males drinking ed gained weight at a faster rate than control males. ed significantly increased the activity of ast in the blood sera of females and, to a lesser degree, of aLt in both males and females drinking ed. ed did not significantly affect the concentration of creatinine or Hba 1c , but significantly increased the concentration of cholesterol in the blood of males from group iV. Conclusions. the prolonged consumption of ed does not affect memory processes, but increases the activity of transaminases and cholesterol concentration in blood sera in the mice model. Key words: memory, cholesterol, energy drink, transaminases.

Introduction. Nicotine is an alkaloid that affects the functioning of the central nervous system and produces dependence. In low doses, it acts as a stimulant and relaxant. Nicotine was reported to have pro-cognitive effects in humans and animals. However, high doses of nicotine are harmful for many organs.The aim of the study was to check whether a 30-day exposure to transdermal nicotine affects memory and biochemical parameters in mice. Materials and method. A total of 32 mice (16 males and 16 females) were used in the experiment. Mice were divided into 4 groups of 8 animals each: I control-females receiving placebo patches for 30 days, II females receiving nicotine patches for 30 days, III control-males receiving placebo patches, IV males receiving nicotine patches. Spontaneous alternation and locomotor activity were examined weekly in a Y-maze. Body mass was recorded daily. On day 30, venous blood samples were obtained and the animals were anaesthetized with CO 2. Their blood was used to measure alanine transaminase (ALT), asparagine transaminase (AST), cholesterol, creatinine and glycosylated haemoglobin (HbA 1 C). Results. Nicotine significantly improved memory in male mice on day 8. It increased ALT and AST activities in males and females, as well as the concentration of cholesterol in their blood sera. Conclusions. In conclusion, transdermal nicotine may produce transient improvement in fresh spatial memory in male mice, but it is not a long-term effect and therefore nicotine does not seem to be appropriate for use in the treatment of neurodegenerative disorders. It elevates blood cholesterol level and thus may increase the risk of atherosclerosis and cardiovascular events; moreover, it negatively affects liver enzymes. Nicotine use is therefore not recommended.