Abstract
It is unclear what contribution food intake and metabolism have in causing weight loss after administering a dose of nicotine equivalent to smoking one to three packs of cigarettes per day because previous studies have been of a very short duration. To address this question, male Sprague Dawley rats were housed in computerized food intake modules and fed 45mg pellets: Group 1 [nicotine injected with 1.4mg/kg/day (free base), fed ad libitum]; and Group 2 [saline injected and pair-fed by computer with Group 2]; and Group 3 [saline injected (i.p.), fed ad libitum]. The rats received 4 equally spaced injections over the dark phase. Treatment consisted of: Phase 1 (nicotine or saline for 14days), Phase 2 (all rats saline for 8days and Phase 3 (pair-fed group "unyoked" for 6days)). Nicotine inhibited food intake over the first 6days. On termination of nicotine, there was no compensatory hyperphagia in either Groups 1 or 2; and their body weight was reduced starting on day 5 until day 28. In another study, rats were housed in an indirect calorimetry system. Saline or nicotine was injected for 14days, as noted above; then all rats were injected with saline for 4days and then no injections for 10days to follow changes in body weight. Energy expenditure (Kcal/Kg0.75) was measured for 18days. Nicotine significantly reduced food intake on 7 of 14days of nicotine injections. The body weight of the nicotine injected rats was significantly reduced starting on day 3 until day 25. There were no differences in energy expenditures of the groups, which suggested that a decrease in food intake and not an increase in metabolism was the reason the rats lost weight after administering nicotine.
Original language | English (US) |
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Pages (from-to) | 92-99 |
Number of pages | 8 |
Journal | Pharmacology Biochemistry and Behavior |
Volume | 95 |
Issue number | 1 |
DOIs | |
State | Published - Mar 2010 |
Keywords
- Pair-fed
- Respiratory quotient
- Smoking
- Weight loss
ASJC Scopus subject areas
- Biochemistry
- Toxicology
- Pharmacology
- Clinical Biochemistry
- Biological Psychiatry
- Behavioral Neuroscience