Social context has differential effects on acquisition of nicotine self-administration in male and female rats

Abstract

Rational Smoking typically begins during adolescence or early adulthood in a social context, yet the role of social context in animal models is poorly understood. Objectives The present study examined the effect of social context on acquisition of nicotine self-administration. Methods Sixty day-old male and female Sprague-Dawley rats were trained to press a lever for nicotine (0.015 mg/kg, IV) or saline infusions (males only) on a fixed-ratio (FR1) schedule of reinforcement across 9 sessions in duplex chambers that were conjoined with either a solid wall or a wall containing wire mesh creating a social context between rat dyads (social visual, auditory, and olfactory cues). In a subsequent experiment, sex differences and dose-dependent effects of nicotine [0 (saline), 0.015 or 0.03 mg/kg, IV] were directly compared in rats trained in the isolated or social context on a schedule progressing from FR1 to FR3. These rats were given 20 sessions followed by 3 extinction sessions. Results We consistently found transient social facilitation of low dose nicotine self-administration in males during the first session. However, across training overall we found social suppression of nicotine intake that was most prominent in females during later sessions. Conclusions Collectively, these findings suggest that at the age of transition from adolescence to adulthood, a social context enhances the initial reinforcing effects of nicotine in males, but protects against nicotine intake during later sessions especially in females. These findings highlight the importance of sex and social context in studying neural mechanisms involved in initiation of nicotine use.

Anti-inflammatory agents for smoking cessation? Focus on cognitive deficits associated with nicotine withdrawal in male mice

“…The use only of male mice is a limitation of this study since several reports show evidences for sex differences in the central effects of nicotine in rodent models Peartree et al, 2017). Although social factors are crucial in smoking dependence in humans, differences in the pharmacokinetic properties of nicotine or the effect of gonadal hormones may underlie some of the sex differences observed (Pogun and Yararbas, 2009).…”

Sex differences in nicotine intravenous self-administration: A meta-analytic review

“…There are also studies that report no sex differences in nicotine IVSA [18,31,44,55,56]. These conflicting findings may be due to methodological differences that influence the magnitude of sex differences, such as the presence of cues [6] or differences in social context [40]. The absence of sex differences in some studies may also be due to small sample sizes that reduce statistical power, thereby decreasing the likelihood of detecting sex differences in IVSA when such differences exist in the population.…”

Social modulation of drug use and drug addiction

“…Most experiments have been conducted on adult males but increasing studies are comparing the influence of sex or development stages. Social isolation initially reduces self-administration of nicotine in males, but enhances nicotine intake during later sessions especially in females (Peartree et al, 2017). Adolescent Sprague-Dawley rats female rats consumed more sweetener-supplemented alcohol in isolation than when group-housed while in the same studies adolescent and adult male consume more alcohol in triads versus when isolate-housed (Varlinskaya et al, 2015).…”