Fast and delayed locomotor response to acute high-dose nicotine administration in adult male rats.

The aim of the present study was to compare the immediate and delayed locomotor response to high-dose nicotine (NIC) administration in rats. The vertical and horizontal activity of behavior in adult male rats exposed to 1 mg/kg NIC or saline (SAL) were tested in a Laboras apparatus for one hour after drug application. Animals were then returned to their cages and housed for another seven days. After this period all animals were placed in Laboras again and their behavioral pattern was retested for another period of one hour (delayed response). Horizontal activity: immediately after nicotine administration animal were less mobile (first 2-minutes interval), when compared with controls. The immobilization effect of nicotine disappeared within 4 minutes and during whole first 10-minutes interval time spent by locomotion did not differ from controls. Locomotion activity of animals treated with nicotine increased robustly in following 10 minutes and remained significantly higher in 2nd, 3rd and 5th 10-minutes interval. Vertical activity: Rearing frequency was significantly lowered by NIC administration in first two minutes of the experiment and the same was found when the duration of rearing was analyzed. Lower rearing intensity of NIC treated animals disappeared in 4 minutes and was finally higher during whole test session as compared with controls. When duration of rearing was analyzed it was significantly longer in NIC treated animals. In majority of observed behavioral aspects there were no differences between NIC treated rats and controls seven days after NIC or SAL treatment. Our results reflect effect of NIC and we conclude that NIC significantly influences behavior of experimental animals.