Nicotine's behavioral actions in the human smoker by self-report depend, in part, on the individual's gender and environment. The purpose of the present experiment was to determine whether effects of nicotine on unconditioned behaviors of rats also depend on sex and environmental conditions. Long-Evans rats (96 males and 96 females) living in individual or grouped housing were administered saline or 12 mg/kg/day nicotine via osmotic minipump for 14 days. Horizontal activity (a measure of overall activity and arousal), vertical activity (a measure of exploratory behavior), and center time (a possible index of anxiety) were measured on Day 10 of drug administration and on Day 2 of nicotine cessation. Group housing decreased horizontal and vertical activity and center time, with effects occurring sooner in females. Nicotine's effects depended on housing and sex. For males, nicotine altered indices of arousal and exploration, increasing these variables for group-housed males but decreasing them for individually housed males. For females, nicotine altered possible indices of anxiety, reducing anxiety for group-housed females. In cessation, housing effects continued in females and appeared more robustly in males. Results indicate that nicotine's chronic effects depend on subjects' sex and living environment.

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The present experiment examined relaxation using different experimental conditions to test whether the effects of individual elements of relaxation could be measured, whether specific effects were revealed, or whether relaxation resulted from a generalized "relaxation response." Sixty-seven normal, male volunteers were exposed to a stress manipulation and then to one of two relaxation (Progressive Relaxation, Music) or control (Attention Control, Silence) conditions. Measurements of attention, relaxation, and stress responses were obtained during each phase of the experiment. All four groups exhibited similar performance on behavioral measures of attention that suggested a reduction in physiological arousal following their relaxation or control condition, as well as a decreased heart rate. Progressive Relaxation, however, resulted in the greatest effects on behavioral and self-report measures of relaxation, suggesting that cognitive cues provided by stress management techniques contribute to relaxation.

Despite the fact that the anxiety-relieving effects of smoking are widely reported by smokers, human laboratory studies have not found consistent evidence for this effect. In animals, contrasting results also have been reported, with Sprague-Dawley rats unaffected by nicotine in behavioral tests of anxiety but with other rat strains (e.g., Wistar, Fischer-344) displaying behaviors indicative of anxiolysis. The present experiment used the social interaction test to evaluate effects of nicotine (12 mg/kg/day) chronically administered via minipump on social and non-social behaviors in 48 male and 48 female Long-Evans rats--a strain that has not previously been evaluated and that is known to differ from Sprague-Dawleys in other behavioral responses to nicotine. Because environmental conditions can alter behavioral effects of drugs, animals lived in either individual or same-sex group housing. Social interactions were measured on day 10 of drug administration and social behaviors (touch, follow, sniff-other, wrestle) as well as non-social behaviors (anxiety-related behaviors: freezing, grooming-self; exploratory behavior: moving) were scored. Group housing decreased social behaviors and increased anxiety-related behaviors. Nicotine's effects depended upon housing condition, such that nicotine further decreased social behaviors and increased anxiety-related behaviors of group-housed animals, with weaker effects in single-housed animals. Overall, the results suggest that nicotine's effects are modified by environmental conditions, and that nicotine administration at this dosage and in this particular rat strain results in anxiogenic effects.