Individual differences in oral nicotine intake in rats

Abstract

To study individual differences in nicotine preference and intake, male and female rats were given free access to a choice of oral nicotine (10 or 20 mg/L) or water for 24 hours/day for periods of at least six weeks, starting at adolescence or adulthood. A total of 341 rats, were used in four different experiments; weight, nicotine intake and total liquid consumption were recorded weekly. Results show that rats can discriminate nicotine from water, can regulate their intake, and that there are readily detected individual differences in nicotine preference. Ward analyses indicated that the animals could be divided into minimum, median and maximum preferring subgroups in all experiments. The effect of saccharine on nicotine intake was also evaluated; although the addition of saccharine increased total intake, rats drank unsweetened nicotine solutions and those with higher preferences for nicotine, preferred nicotine over water with or without saccharine added. Nicotine reduced weight gain and the effect was more pronounced in females than males. The average nicotine consumption of adolescent rats was higher than adults and nicotine exposure during adolescence reduced nicotine intake in adult rats. About half of the rats which had access to nicotine as adolescents and also as adults had a persistent pattern of consumption; the behavior was very stable in the female minimum preferring groups and a much higher ratio of rats sustained their adolescent behavior as adults. The change in preference was more pronounced when there was an interval between adolescent and adult exposure; female rats showed a more stable behavior than males suggesting a greater role for environmental influences on males. In conclusion, marked individual differences were observed in oral nicotine intake as measured in a continuous access 2-bottle choice test. Age and sex of the subjects and previous exposure to nicotine are significant factors which affect preference in rats.

Maternal nicotine exposure during lactation alters food preference, anxiety-like behavior and the brain dopaminergic reward system in the adult rat offspring

“…On the other hand, in the absence of nicotine (last 3 days of lactation), dams showed lower food intake with higher serum and milk leptin levels [78]. Our results differ from Nesil et al [74], which showed decreased body mass in female rats exposed to nicotine, but they were neither lactating nor pregnant. Also, there are differences between studies regarding the administration of nicotine.…”

Insight into the Potential Factors That Promote Tobacco Use in Vulnerable Populations

“…For example, adolescent rodents display greater nicotine CPP as compared to adults across a wide range of experimental protocols, nicotine doses, and routes of administration [15][16][17][18][19][20][21][22]. Studies using IV and oral SA procedures have also shown that nicotine intake is higher in adolescent versus adult rats [23][24][25][26][27][28] and mice [29]. High doses of For a recent and comprehensive review of the physical and affective states produced by withdrawal in rodents and humans, the reader is referred to Hall et al [4] nicotine also produce aversive effects that are lower in adolescent versus adult rats [18,30].…”

Nicotine withdrawal in selectively bred high and low nicotine preferring rat lines

“…Adult male and female Sprague Dawley rats (F 0 , n = 77), obtained from Ege University Animal Breeding Facility, were subjected to oral nicotine self-administration, as the founding population for the selective breeding of the high-NP and low-NP lines (Collins et al, 2012;Nesil et al, 2011). Rats were kept in same-sex groups with ad libitum access to food and water and were housed under standard laboratory conditions (20-22°C, 12-12 h light-dark cycle) when they were not being used for breeding or testing.…”

“…When being tested for oral nicotine intake, each rat was housed individually. After the termination of oral nicotine self-administration, rats (n = 48) that consumed the highest and lowest nicotine were selected [high-NP Female (n = 14), Male (n = 13); low-NP Female (n = 7), Male (n = 14)], using the Ward Cluster Method (Nesil et al, 2011), as breeders for the next generation. In the following generations (F 1 -F 8 ) the highest nicotine consuming of the high-NP and the lowest of the low-NP were selected and outbred.…”

“…Oral nicotine self-administration was performed as described earlier (Nesil et al, 2011). Briefly, rats were given access to either nicotine in water [Sigma, (−) nicotine hydrogen tartrate] or plain water using a two bottle free-choice method.…”