The Adult Learner’s Quest: W.E.B. Du Bois As Vicarious Mentor

The intentional adult learner is intellectually and emotionally in a perpetual “act of seeking.” The search is for purpose, meaning, humanistic dialogue, self-awareness, creative adventure, and life-affirming experiences. This act of seeking makes the on-going, existential life journey an educational commitment; a continuing involvement with both abstract ideas and concrete reality. Age dims the eyes, not visionary possibilities; slows the reflexes, not the reflective skill that helps define the person as a thinking, questioning, questing being

Social environment modulates morphine sensitivity: A partial role of vasopressin V1b receptor

Social factors influence drug abuse in adolescents; this is partially attributed to peer pressure in humans. Similarly, using rodent models, some research suggests that social housing condition can influence rodents' drug taking behavior. Despite this, few studies have examined the role that intoxicated peers have on drug-naive cage-mates. This dissertation examined how social environment affects opioid sensitivity and hormone production. This was accomplished by comparing the opioid sensitivity of mice housed in mixed cages (some animals received opioids and some were drug-naive) to cages where all the mice were treated with the same drug (all saline or all morphine). These studies identified an adolescent-specific vulnerability to social environment-induced alteration of morphine sensitivity. Interaction with drug-intoxicated cage-mates enhanced locomotor sensitivity in previously drug-naive males and altered their production of testosterone. Conversely, interaction of morphine experienced mice with drug-naive cage-mates afforded protection from the rewarding properties of morphine. In other words, morphine-treated mice housed with drug-naive cage-mates demonstrated attenuated reward compared to morphine-treated mice housed with other morphine-treated mice. In addition, part of the neurobiological basis of the social-environment effect was identified. Antagonism of V1b receptors decreased morphine reward in morphine-treated mice housed only with other morphine-treated mice. These results suggest a role of vasopressin in the peer influence on drug sensitivity observed in adolescents. This body of work further elucidates the role of peer influence on opioid sensitivity. Future studies should further reveal the role of healthy peer relationships and should aid in combating drug abuse in this at-risk demographic

Social environment modulates morphine sensitivity: A partial role of vasopressin V1b receptor

Social factors influence drug abuse in adolescents; this is partially attributed to peer pressure in humans. Similarly, using rodent models, some research suggests that social housing condition can influence rodents' drug taking behavior. Despite this, few studies have examined the role that intoxicated peers have on drug-naive cage-mates. This dissertation examined how social environment affects opioid sensitivity and hormone production. This was accomplished by comparing the opioid sensitivity of mice housed in mixed cages (some animals received opioids and some were drug-naive) to cages where all the mice were treated with the same drug (all saline or all morphine). These studies identified an adolescent-specific vulnerability to social environment-induced alteration of morphine sensitivity. Interaction with drug-intoxicated cage-mates enhanced locomotor sensitivity in previously drug-naive males and altered their production of testosterone. Conversely, interaction of morphine experienced mice with drug-naive cage-mates afforded protection from the rewarding properties of morphine. In other words, morphine-treated mice housed with drug-naive cage-mates demonstrated attenuated reward compared to morphine-treated mice housed with other morphine-treated mice. In addition, part of the neurobiological basis of the social-environment effect was identified. Antagonism of V1b receptors decreased morphine reward in morphine-treated mice housed only with other morphine-treated mice. These results suggest a role of vasopressin in the peer influence on drug sensitivity observed in adolescents. This body of work further elucidates the role of peer influence on opioid sensitivity. Future studies should further reveal the role of healthy peer relationships and should aid in combating drug abuse in this at-risk demographic

Effects of Environmental Conditions on c-fos Expression in Rat Nucleus Accumbens After Remifentanil

Previous studies have shown that adolescents raised in impoverished conditions are more likely to develop drug abuse in adulthood. In addition, both stress-inducing living conditions (impoverishment/isolation) and drugs of abuse may lead to an increase in the c-fos transcription factor in the reward circuit of the brain, particularly in the nucleus accumbens. The aim of the current study was to quantify the number of c-fos positive cells in the nucleus accumbens of enriched and isolated rats exposed to the opioid remifentanil. Thirty-two male Sprague-Dawley rats were raised in either enriched or isolated conditions for one month, after which they received 10 i.v. infusions of 3 μg/kg remifentanil or saline through the jugular vein. Eighty-five minutes after the last infusion, rats underwent perfusions. After immunohistochemistry was performed on tissue containing the nucleus accumbens, the average number of c-fos positive cells per slice was obtained using ImageJ. Using a 2x2 between subjects ANOVA, with drug and environment as factors, this research demonstrated a main effect of environment on c-fos expression in the nucleus accumbens, with isolated rats expressing more c-fos positive cells than enriched rats. However, there was no significant effect of drug treatment, suggesting that remifentanil did not increase total c-fos as expected. This study demonstrated the cellular consequences of being raised in different living conditions, as it showed that individuals raised under high levels of stress may be at risk of altered cell signaling and gene expression in the reward system of the brain

Modified Single Prolonged Stress Reduces Cocaine Self-Administration During Acquisition Regardless of Rearing Environment

Until recently, there were few rodent models available to study the interaction of post-traumatic stress disorder (PTSD) and drug taking. Like PTSD, single prolonged stress (SPS) produces hypothalamic-pituitary-adrenal (HPA) axis dysfunction and alters psychostimulant self-administration. Other stressors, such as isolation stress, also alter psychostimulant self-administration. However, it is currently unknown if isolation housing combined with SPS can alter the acquisition or maintenance of cocaine self-administration. The current study applied modified SPS (modSPS; two hours restraint immediately followed by cold swim stress) to rats raised in an isolation condition (Iso), enrichment condition (Enr), or standard condition (Std) to measure changes in cocaine self-administration and HPA markers. Regardless of rearing condition, rats exposed to modSPS had greater corticosterone (CORT) release and reduced cocaine self-administration during initial acquisition compared to non-stressed controls. In addition, during initial acquisition, rats that received both Iso rearing and modSPS showed a more rapid increase in cocaine self-administration across sessions compared to Enr and Std rats exposed to modSPS. Following initial acquisition, a dose response analysis showed that Iso rats were overall most sensitive to changes in cocaine unit dose; however, modSPS had no effect on the cocaine dose response curve. Further, there was no effect of either modSPS or differential rearing on expression of glucocorticoid receptor (GR) in hypothalamus, medial prefrontal cortex, amygdala, or nucleus accumbens. By using modSPS in combination with Iso housing, this study identified unique contributions of each stressor to acquisition of cocaine self-administration