Comparisons between young adult waterpipe smokers and nonsmokers' reactions to pictorial health warning labels in Lebanon: a randomized crossover experimental study.

This study compares the impact of pictorial health warning labels (HWLs) and their placements on waterpipe parts (device, tobacco and charcoal packages) on health communication outcomes between waterpipe smokers and nonsmokers in Lebanon. An online randomized crossover experimental study was conducted among young adults (n = 403, August 2021) who observed three conditions of HWLs: pictorial HWLs on the tobacco package, pictorial HWLs on all waterpipe's parts and text-only HWL on the tobacco package in random order. Participants completed post-exposure assessments of health communication outcomes after each image. Using linear mixed models, we examined the differences in the effect of HWL conditions on several outcomes (i.e. warning reactions) between waterpipe smokers and nonsmokers, controlling for confounders (i.e. age, sex). Nonsmokers reported greater attention (ß = 0.54 [95% confidence interval: 0.25-0.82]), cognitive elaboration (0.31 [0.05-0.58]) and social interaction (0.41 [0.18-0.65]) for pictorial HWLs on the tobacco packages than text-only compared with smokers. Pictorial HWLs on three parts versus one part elicited higher cognitive reactions and perceived message effectiveness in nonsmokers compared with waterpipe smokers. These findings provide valuable information for policymakers about the potential of implementing HWLs specific to waterpipes to prevent their use among young adults and limit tobacco-related morbidity and mortality in Lebanon.

Mesocortical dopamine depletion and anxiety-related behavior in the rat: sex and hemisphere differences.

The mesocortical dopamine (DA) system of the rat plays an important role in prefrontal cortex (PFC) regulation of stress and emotion and exhibits functional hemispheric asymmetry for such processing. Since few studies examine sex differences in this context, we compared the effects of left vs. right unilateral PFC DA depletion in males and females in several behavioral situations associated with anxiety or aversion. Adult rats received unilateral injections of 6-hydroxydopamine (6-OHDA) or vehicle in the ventromedial (vm) PFC. Behavioral tests included a predator odor burying test, elevated plus maze and sucrose consumption with simple taste aversion. Tissue analysis confirmed that vmPFCs injected with 6-OHDA were depleted of DA (75-85%) compared to controls. Burying behavior and sucrose consumption were affected only by left lesions, similarly in both sexes. However, risk assessment behaviors were affected by right lesions in opposite directions in males and females. Behaviors modified preferentially by the left cortex thus showed less evidence of sex differences than those modulated by the right. While mesocortical DA depletion effects are lateralized, the nature of these effects can vary with sex and specific behavior. Such findings may be clinically significant, given the large gender differences in the incidence of mood and anxiety disorders, which also show many lateralized prefrontal abnormalities.

Role of sex in the neurochemical and neuroendocrine correlates of paw preference in the rat.

Handedness in humans and paw preference (PP) in rodents have been associated with neural and physiological correlates, which frequently appear to be sex-specific. The present study examines sex differences in the effects of differential PP on post mortem measures of regional monoamine activity in adult Long-Evans rats. The effects of PP on neuroendocrine function were also assessed by measuring plasma adrenocorticotropic hormone (ACTH) in response to a 30-min restraint stress. Most rats showed strong individual PP. Males (n=27) and females (n=26) did not differ in the direction or strength of their PP with nearly equal numbers of left and right-pawed rats. However, many Sex×PP interactions were noted in regional neurochemical measures, and most effects of PP were bilateral in nature and sex-specific. In males, Left PP (relative to Right PP) was associated with reduced striatal dopamine (DA) levels and amygdala DA metabolism bilaterally. In females, Left PP was associated with a bilateral upregulation of DAergic metabolism in both prefrontal cortex and nucleus accumbens, increased amygdala serotonin metabolism, and a (right) unilateral increase in amygdala DA. As in previous studies, some correlations were also noted between PP and asymmetrical or unilateral monoamine measures. As well, rats with strong PP, independent of direction or sex, had lower basal ACTH and more robust stress responses than rats with weak PP, suggesting a possible adaptive advantage to strong lateralization. Overall, sex differences were found only regarding effects of the direction of PP, not its magnitude. The findings suggest that the direction of PP affects distinct bilateral networks of structures sex-dependently. Such fundamental influences of PP on functional brain organization have implications for a wide array of processes under monoaminergic modulation in these brain regions, and may further our understanding of the numerous human examples of gender and handedness interactions across several modalities.