Matching Items (3)
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- All Subjects: Nicotine
- Creators: Neisewander, Janet
- Member of: Barrett, The Honors College Thesis/Creative Project Collection
Description
Research suggests that the more positive the first drug experience, the more likely addiction will develop. Since smoking is initiated in a social setting, it is surprising how little is known about social context effects on acquisition of nicotine self-administration. We investigated this issue in rats during late adolescence using conjoined self-administration chambers that had a removable shared wall. Rats were assigned to training conditions with either a solid black plexiglass or wire mesh partition in place throughout 22 subsequent 2-hour daily training sessions. Initially, 58 day-old (late-adolescent) male and female rats received 2, 30-min habituation sessions/day over 2 consecutive days, with only an inactive lever present. Sessions began with presentation of a retractable lever and thereafter each response on that lever resulted in simultaneous delivery of saline or 1 of 2 doses of nicotine (0.015 or 0.030 mg/kg, IV) and lever retraction for a 20-second time out. The findings indicate that the social context inhibits nicotine self-administration in female rats during the development of addiction, but has little effect on the initial stages of drug acquisition. Furthermore, the data suggest that in male rats the social context enhances responding independent of nicotine, but has few effects on nicotine self-administration during the development of addiction. The findings have important implications for substance use disorders.
ContributorsDufwenberg, Martin (Author) / Neisewander, Janet (Thesis director) / Deviche, Pierre (Committee member) / Peartree, Natalie (Committee member) / Barrett, The Honors College (Contributor) / School of Mathematical and Statistical Sciences (Contributor) / School of Politics and Global Studies (Contributor) / School of Life Sciences (Contributor)
Created2015-05
Description
Abstract White matter thickness correlates with various mental illness. Commissure white matter tracts are responsible for interconnecting the same cortical area in both hemispheres. Injury to the brain can result in thinning and shrinkage even collapsing and detachment of the white matter tracts' myelin sheaths. Injury can affect cognitive function and time points are essential for therapeutic intervention. Research is beginning to identify gradual long-term neurodegenerative effects. With the advancement of brain imaging technology, we know that Wallerian degeneration has a significant negative impact on the white matter tracts throughout the brain (Johnson, Stewart, & Smith, 2013). If major tracts become injured like, the corpus callosum, then it can affect interhemispheric communication. Once myelin is damaged the axon becomes vulnerable, and the mechanisms of nerve recovery are not well known. Myelin sheath recovery has been studied in hopes to proliferate the oligodendrocytes that make up for the atrophied myelin. Neurotoxic chemicals released at activation of macrophages which hinders the brains ability to proliferate myelin protein needed for myelin differentiation adequately. In the central nervous system myelin has mechanisms to recover. Neurogenesis is a naturally occurring recovery mechanism seen after brain injury. Understanding the time points in which brain recovery occurs is important for treatment of diffuse injuries that cannot be identified through some imaging techniques. To better understand critical timepoints of natural recovery after brain injury can allow further investigation for early intervention to promote adequate recovery.
ContributorsLiptow, Kristen Ashley (Author) / Neisewander, Janet (Thesis director) / Law, L. Matthew (Committee member) / School of Social and Behavioral Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2018-12
Description
Previous findings from our lab have demonstrated that nicotine and social reward have synergistic effects when experienced together versus when experienced separately. The purpose of this experiment is to understand the neural mechanisms underlying this synergistic effect by quantifying Fos protein, a marker for neural activation, in various brain regions. We utilized the conditioning place preference (CPP) model to assess reward. Four groups of adolescent male rats (n=120) were given either nicotine (Nic) (0.1 mg/kg/mL) or saline (Sal) and were placed in the CPP apparatus either with a social partner (Soc) or alone (Iso). Thus, groups were: 1.)Sal+Iso, 2).Sal+Soc, 3).Nic+Iso, 4).Nic+Soc. Brains of some the rats (n=40) were collected for Fos staining 90 minutes after the last conditioning session to obtain Fos data in response to direct exposure to the stimuli. The following regions were analyzed for Fos expression: central amygdala (CeA), medial amygdala (MeA), basolateral amygdala (BLA), nucleus accumbens core (NAcCore), and nucleus accumbens shell (NAcShell). Place preference changes occurred in socially-conditioned groups reflecting social reward and in nicotine-conditioned groups reflecting nicotine reward. As expected, the Sal+Iso control group failed to display a preference change. Fos data revealed a significant increase in Fos expression in the CeA, MeA, NAcCore and NAcShell for socially-conditioned animals and a significant decrease in the NAcCore for nicotine-conditioned groups. Experiencing both social and nicotine rewards together appeared to produce greater activation in the BLA. However, there was an increase in Fos expression in the negative control group relative to Nic+Iso group. The results of CPP suggest that social, nicotine and their combination are rewarding. The combination of the nicotine and social reward could have been more rewarding than social and nicotine separately, but the test was not sensitive to reward magnitude. The increase in Fos expression in the negative control group in the BLA could be due to isolation stress. Overall, these results suggest that these brain regions had greater activation to social reward.
ContributorsGoenaga, Julianna Gloria (Author) / Neisewander, Janet (Thesis director) / Orchinik, Miles (Committee member) / Olive, Michael (Committee member) / Barrett, The Honors College (Contributor) / School of Historical, Philosophical and Religious Studies (Contributor) / School of Life Sciences (Contributor)
Created2013-05