[Influences of free intake of nicotine on several circadian rhythms in rats].
Male Wistar rats, aged 4 weeks, were kept in a temperature controlled room with a 12 hr light-dark cycle and given food and water ad libitum. The nicotine-treated group of rats was given water containing nicotine, which was estimated to be 10 mg/kg/day, for 40 days. Spontaneous motor activities, drinking activities and serum corticosterone levels showed circadian rhythms characteristic of a nocturnal animal in both the control and the nicotine-treated groups. As compared to the control group, however, the nicotine-treated group showed an increase in ambulatory activities, a decrease in drinking activities and a diminution of weight gain. In comparison with diurnal variations, serum corticosterone levels and liver nicotine oxidase activities increased in the nicotine-treated group during the dark period. However, the pattern of circadian rhythms characteristic of a nocturnal animal were not altered.
D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002940:Circadian Rhythm / Q000187:drug effects*; D003345:Corticosterone / Q000097:blood; D003577:Cytochrome P-450 Enzyme System / Q000032:analysis; D004327:Drinking Behavior / Q000187:drug effects; D008099:Liver / Q000201:enzymology; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D009538:Nicotine / Q000494:pharmacology*; D009929:Organ Size / Q000187:drug effects; D010088:Oxidoreductases / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains
D009538:Nicotine; D003577:Cytochrome P-450 Enzyme System; D010088:Oxidoreductases; C034523:nicotine oxidase; D003345:Corticosterone