Dietary Restriction and Nicotine can Reduce Anxiety in Female Rats

Abstract

Anxiety may play a role in the initiation of smoking and there is evidence to suggest that sex and age may predetermine responses to nicotine. At present, the greatest increase in smoking is in women and it is often accompanied by dieting. The purpose of the present study was to investigate how the impact of dietary restriction might modify the effects of nicotine in female adult and adolescent rats. The effects of nicotine in the elevated plus-maze test of anxiety were compared in free-feeding animals and those subjected to dietary restriction that reduced body weight to 85% of free-feeding weight. In nondeprived adult females, nicotine (0.05-0.5 mg/kg, s.c.) reduced the percentage of time spent on the open arms, indicating anxiogenic effects. However, the effects of nicotine were dramatically changed in food-restricted adult females and 0.05 mg/kg had a striking anxiolytic effect. No significant effects of nicotine were found in the adolescent female rats, suggesting a role of circulating sex hormones in modulating nicotine's effects on anxiety. However, in the adolescent females, dietary restriction significantly increased the percentages of time spent and entries onto the open arms, without changing closed arm entries, indicating an anxiolytic effect. These results raise the important possibility that, in prepubertal girls, dietary restriction may have anxiolytic effects and this might contribute to the onset of anorexia. Circulating female hormones reduce this effect, but in adult females the combination of dietary restriction and nicotine may have important anxiolytic effects that impact on the initiation of regular smoking.

Methyl Donor-Deficient Diet during Development Can Affect Fear and Anxiety in Adulthood in C57BL/6J Mice

“…In contrast, another report with male and female mice did not observe such decrease in anxiety-like behavior [40]. Alternatively, because behavioral changes in our study were observed in very similar ways in both experimental groups, it should be considered that the food restriction itself might have had the anxiolytic effect on juvenile mice, consistent with previous dietary restriction studies [41], [42], [43]. In the present study, locomotor activities among groups did not affect behavioral results because the total distance during the EPM and %freezing during acclimation period were not significantly different among groups.…”

Neonatal Exposure of Rats to Antidepressants Affects Behavioral Reactions to Novelty and Social Interactions in a Manner Analogous to Autistic Spectrum Disorders

“…A recent metanalysis of sensory processing in autism, has described sensory processing alterations as universally present in autistic individuals (Genn et al, 2003). Both primary (auditory, visual, tactile and olfactory) and multimodal sensory processing have been reported as abnormal in individuals with ASD (Cohen et al, 2004).…”

Comparison of anxiety-like behavior in adolescent and adult sprague-dawley rats.

“…Animals models have provided conflicting findings regarding age differences in anxiety-like behavior. Studies in rodents have reported indices of decreased anxiety in adolescents (Andrade, Tome ´, Santiago, Lu ´cia-Santos, & Spera de Andrade, 2003;Genn, Tucci, Thomas, Edwards, & File, 2003;Imhof, Coelho, Schmitt, Morato, & Carobrez, 1993), increased anxiety in adolescents (Doremus, Brunell, Varlinskaya, & Spear, 2003;Faraday, Elliott, & Grunberg, 2001;Faraday, Elliott, Phillips, & Grunberg, 2003;Imhof et al, 1993;Walker, March, & Hodgson, 2004), or equivalent levels of anxiety in adolescents relative to adults (Faraday et al, 2003;Hascoe ¨t, Colombel, & Bourin, 1999;Stone & Quartermain, 1998;White et al, 2002). These discrepancies are likely to be mediated by a combination of factors that include strain, gender, age at testing, and the test environment.…”

“…However, responses to stressors have been reported to differ between adolescent and adults. In many cases, adolescents appear to be more sensitive to stress-induced changes in neurobehavioral function (Choi & Kellogg, 1996;Genn et al, 2003;Stone & Quartermain, 1998;Wilson et al, 2000). For example, social stress more potently increases anxiety-like behavior in the elevated plus-maze in adolescent rats (Stone & Quartermain, 1998), and restraint stress preferentially reduces ambulation and rearing in an open field in adolescent rats (Wilson et al, 2000).…”