Effect of the single-dose of nicotine-administration on the brain bioelectrical activity and on behaviour in immature 12-day-old rats.

A variety of current studies is concentrated on the effect of short-term or long-term administration of nicotine in humans and in animals. The aim of this study was to investigate the effect of nicotine after a single administration in two different doses on the brain bioelectrical activity and on behaviour and motor activity in young, immature rats. Male Wistar albino rats, 12-day-old, were used in the experiment. Two groups were administrated by one intraperitoneal (i.p.) injection of nicotine in two various doses. The last (the third) group, which was given one i.p. saline injection, served as a control group. The group with lower dose of nicotine (0.75 mg/kg body weight) showed only mild alteration of the electrocorticogram (ECoG), and no behavioural or motor changes. In the second group (with higher dose of nicotine--1.00 mg/kg), epileptiform discharges manifested in about 50% of animals. Those animals showed also changes in motor activity (tremor of hindlimbs), but only slightly expressed within the time when epileptiform changes occurred in the ECoG. Routine behaviour and locomotion was observed only in a part of animals. In the third group (control group) no changes in bioelectrical activity, in behaviour or in motor activity were observed. We conclude that even a single dose of nicotine can evoke alteration in the ECoG, in behaviour and in motor activity of immature rats. On the other hand, the quantity, quality and length of ECoG abnormalities as well as parameters of behaviour were closely related to the dose of nicotine.