ABSTRACT
Nicotine, the major specific alkaloid in tobacco smoke, exhibits widespread pharmacological effects and may contribute to deterioration in behaviour. The present study thus examined the effects of its chronic administration on some cognitive and mood associated behaviours. Adult rats weighing between 150 and 200g were randomly divided into 4 groups each of 5 females and 5 males. Three groups were administered graded doses of nicotine at 0.25, 2 and 4mg/kg body weight via subcutaneous injections. One group served as control and received normal saline (vehicle for nicotine). Behavioural tests were performed using the Y-maze, elevated-plus maze (EPM) and tail suspension tests (TST) at various time points. Nicotine produced no significant effect in spontaneous alternation on Y-maze, nor on six parameters scored on EPM (open arm entries, time spent in open arms, time per open arm entries, open/closed arm quotient, closed arm entries, and total arm entries), and also no significant effect on immobility time in TST. This lack of effects was observed to be independent of sex and dose administered. The study shows that nicotine does not produce long-term changes in some cognitive and mood associated behaviours, thus suggesting it could be well tolerated even following chronic administration.
ABSTRACT
BACKGROUND: Nicotine has shown potential therapeutic value for neurodegenerative diseases though there are concerns that it may induce behavioural deficits. PURPOSE: The present study sought to determine the effect of chronic nicotine administration on overall motor functions and coordination. METHODS: Forty adult female and male Wistar rats were randomly grouped into 4 groups. Treated groups were administered nicotine via subcutaneous injections at doses of 0.25, 2 and 4 mg/kg body weight for 28 days. Control groups received normal saline. All animals were monitored for the first few minutes after each injection for any observed immediate effect of drug administration. Motor associated behavioural tests performed include: open field test, string test for grip strength and limb impairment, movement initiation and step test. RESULTS: Nicotine induced muscular convulsions within the first 1-5 minutes following daily subcutaneous injections, throughout the period of administration. This was observed to be more severe in females. Nicotine did not produce major alterations in overall motor functions and coordination in both females and males. CONCLUSION: The present study shows chronic nicotine treatment produces muscular convulsion but no major deficit in overall motor function and coordination and that any observed alterations may just be transient effects.
