This investigation was an analysis of the interaction of adolescent exposure to methylphenidate (MPH; trade name: Ritalin) on nicotine sensitization and conditioned place preference (CPP) in a rodent model and underlying mechanisms of this effect. Animals were treated IP with 1 mg/kg MPH or saline using a ―school day‖ regimen of five days on, two days off, from postnatal day (P) 28-50. During the final two weeks of MPH treatment, animals were either behaviorally sensitized to nicotine (0.5 mg/kg free base) or saline for 10 days, or conditioned to nicotine or saline using the CPP behavioral paradigm. In addition, three days after behavioral sensitization was complete, animals were analyzed for stress behavior using the forced swim stress behavioral test. In addition, 24 hours after post-test conditioning animals were analyzed for the effect of a clinically relevant dose of pre-exposed MPH (1mg/kg) and nicotine treatment on the expression of BDNF in the nucleus accumbens and dorsal hippocampus. Behavioral results revealed that adolescent pre-exposure to MPH blunted nicotine behavioral sensitization in both male and female rats during the first week of testing. However, MPH enhanced nicotine CPP in both adolescent male and female rats. Interesting, animals administered MPH demonstrated a significantly decreased latency to immobility in the forced swim stress behavioral test. In addition, pre-exposure to a 1 mg/kg dose of MPH appears to have sensitized the BDNF response to nicotine in females as compared to all other groups.

Neuropathic pain affects up to 50% of the 29 million diabetic patients in the United States. Neuropathic pain in diabetes manifests as a disease of the peripheral and central nervous systems. The prevalence of type 2 diabetes is far greater than type 1 (90%), yet the overwhelming focus on type 1 models this has left the mechanisms of pain in type 2 diabetes largely unknown. Therefore I aimed to improve the current mechanistic understanding of pain associated with type 2 diabetes using two preclinical rodent models: Zucker Diabetic Fatty rats and db/db mice. In addition, I highlight the translational importance of simultaneous measurement of evoked/sensory and non-evoked/affective pain-related behaviors in preclinical models. This work is the first to show a measure of motivational-affective pain in a model of type 2 diabetes. I used methodological approaches including: (1) immunohistochemical and calcium imaging to assess stimulus-evoked sensitization; (2) measurement nociceptive behaviors and evoked sensory thresholds as well as pain affect using novel mechanical conflict avoidance and conditioned place preference/aversion assays; (3) pharmacological and genetic manipulation of methylglyoxal, TRPA1, AC1, and PPARγ. I hypothesized that the thiazolidinedione class of peroxisome proliferator-activated receptor gamma (PPARγ) agonists would reduce neuropathic pain-like behavior and spinal neuron sensitization in traumatic nerve injury and type 2 diabetes. As PPARγ is a nuclear receptor, and already targeted clinically to promote cellular insulin sensitization to reduce hyperglycemia, sustained changes in gene expression are widely believed to be the mechanism of pain reduction. In two separate research aims, I challenged this view and tested whether the PPARγ agonist pioglitazone would (1) rapidly alleviate neuropathic pain through a non-genomic mechanism and (2) reduce painful sensitization in nociceptive and neuropathic pain models independent from lowering blood glucose. I aimed to investigate the contribution of the glucose metabolite methylglyoxal to painful type 2 diabetes. I tested the hypothesis that methylglyoxal produces nociceptive, evoked, and affective pain that is dependent on activation of the sensory neuron cation channel TRPA1 and the secondary messenger enzyme AC1. I also tested whether pioglitazone or the novel methylglyoxal scavenging peptide GERP10 could alleviate painful type 2 diabetes.

Selective Mu Opioid Receptor (MOR) antagonists possess immense potential in the treatment of opioid abuse/addiction. Utilizing the “message-address” concept, our laboratory reported a novel, reversible, non-peptide MOR selective antagonist 17-cyclopropylmethyl-3,14β-dihydroxy-4,5α-epoxy-6β-[(4՛-pyridyl)carboxamido]morphinan (NAP). Molecular modeling studies revealed that the selectivity of NAP for the MOR is because of a π-π stacking interaction of its pyridine ring with the Trp318residue in theMOR. Pharmacological characterization showed that NAP is a P-glycoprotein substrate, thereby limiting its use in the treatment of opioid abuse/addiction. Thus, to modify NAP, we replaced the pyridine ring with its isosteric counterpart thiophene. Isosteric replacement could lead to development of compounds with different pharmacologic properties. Additionally, exploring other ring systems would diversify and enrich our library of compounds and aid in establishing a comprehensive structure-activity relationship. Therefore, newly synthesized compounds included thiophene derivatives of 6α/β-naltrexamine with potential to be used in the treatment of opioid abuse/addiction. Preliminary in vivo screening revealed that compounds 8 and 11 could be acting as antagonists. To aid in the design and synthesis of newer generation of MOR selective analogs, a 3-Dimensional Quantitative Structure-Activity Relationship (3D-QSAR) Comparative Molecular Field Analysis (CoMFA) on 6β-N-heterocyclic substituted naltrexamine derivatives was conducted. After rigorous optimizations, the best CoMFA model possessed low predictive power. Results obtained suggested that small structural changes could lead to significant change in binding modes of these ligands. To further validate this observation, molecular docking studies were performed which revealed that these ligands indeed possessed multiple distinct binding modes thereby offering rationale for the CoMFA results. Thus, overall this study furnished useful information about the complexity of protein-ligand interactions which will aid in designing more potent and selective MOR ligands.

Drugs of abuse have a long history in humanity. Currently however, a subject of great interest is the phenylalkylamine family of drugs. Not only is the abuse liability of interest but also the potential therapeutic expansion of the capabilities of this family of drugs by utilizing the unique stereospecific effects of the newly discovered hybrid compounds. Based upon prior data of N-Alkyl 4-MA the enantiomers of N-Methyl, N-Ethyl, and N-Propyl were analyzed in hDAT, hNET, and hSERT. It was found that there was a negative correlation between chain length and potency and dopaminergic component. In agreement with the currently established paradigm it was also found that in almost all cases the S(+) enantiomer was the more potent.

Self-injurious behavior (SIB) is a complex phenotype that occurs with an increasing prevalence of about 7-34% in humans and 10-12% in non-human primates (NHPs). This study evaluated the efficacy of probiotic Lactobacillus reuteri as a treatment for self-injurious behavior (SIB) and sleep disruption in rhesus macaques. The treatment was proposed to alleviate mild self-biting, sleep disruption, and reduce chronically elevated hypothalamic-pituitary-adrenocortical (HPA) axis activity, all hallmark features of monkeys with this condition. The probiotic preparation included two strains of L. reuteri (L. reuteri ATCC PTA 6475 & L. reuteri DSM 17938) containing on average 200 million colony forming units per chewable tablet. The study was conducted on 14 rhesus macaque monkeys (9 males) housed at the University of Massachusetts Amherst. To our knowledge this is the first time that a Lactobacillus strain has been used as a treatment for SIB in rhesus macaques. This study utilizes motion-activated infrared camera technology, modified enzyme-immunosorbent-assays (EIAs) techniques to measure hair cortisol concentrations, and daily behavioral observations to provide an overall assessment of the behavioral, physiological, and sleep associated implications of probiotic treatment on SIB and control non-human primates (NHPs). Administration of L reuteri modestly decreased biting behavior in monkeys with SIB (F(2,12) = 5.64, p= 0.02) and showed overall decrease in nighttime activity across all subjects but did not normalize SIB to nonSIB values. Hair cortisol values are pending. These findings and the findings of previous work further strengthen the argument for probiotics as an efficacious treatment for SIB behavior.

How does a nervous system orchestrate compound behaviors? Finding the neural basis of behavior requires knowing which neurons control the behavior and how they are connected. To accomplish this we measured and manipulated neural activity in a live, behaving animal with a completely defined connectome. The C. elegans escape response is a compound behavior consisting of a sequence of behavioral motifs. Gentle touch induces a reversal and suppression of head movements, followed by a deep turn allowing the animal to navigate away from the stimulus. The connectome provides a framework for the neural circuit that controls this behavior. We used optical physiology to determine the activity patterns of individual neurons during the behavior. Calcium imaging of locomotion interneurons and motor neurons reveal unique activity profiles during different motifs of the escape response. Furthermore, we used optogenetics and laser ablations to determine the contribution of individual neurons to each motif. We show these that the suppression of head movements and turning motifs are distinct motor programs and can be uncoupled from the reversal. The molecular mechanisms that regulate these motifs involve from signaling with the neurotransmitter tyramine. Tyramine signaling and gap junctions between locomotion interneurons and motor neurons regulate the temporal orchestration of the turning motif with the reversal. Additionally, tyramine signaling through a GPCR in GABAergic neurons facilitates the asymmetric turning during forward viii locomotion. The combination of optical tools and genetics allows us to dissect a how a neural circuit converts sensory information into a compound behavior.

In an attempt to meet monetary-driven mandates to improve student achievement test scores, administrators are replacing physical education activities with subject matter classes in many American schools. This practice negates the positive contributions of physical activity to academic performance and student fitness. Guided by self-efficacy theory, this study assessed the impact of optimal versus minimal physical fitness state on student academic achievement. The study sample included 5,416 9th grade students from the same school district who completed a minimum of 5 of the 6 components of the FITNESSGRAM tests, and who also completed the math and English language arts (ELA) portions of the California Standards Test. The independent variables were optimal and minimal physical fitness based upon completing 6 or 5 FITNESSGRAM components, respectively. Analyses included independent samples t tests, ANOVA, and Dunnet's C test to detect differences in mean academic scores with gender and ethnicity as covariates. Optimally fit students had significantly higher (p < 0.05) scores in math and ELA tests relative to minimally fit students. Female academic test scores tended to be higher than male scores in both academic tests. School officials, when contemplating curricular programs devoid of a physical education component, might judiciously reassess the positive effects of physical fitness upon academic achievement and the associated biopsychosocial benefits for their students. Physically fit and academically enriched students may provide a foundation for positive social change directed at engendering a healthier, motivated, and productive citizenry.

Traumatic brain injury (TBI) incidence rates are increasing among the U.S. population and represent substantial acute and chronic care costs. A confounding factor in TBI treatment is the incidence rates of concomitant mental health disorders including depression, anxiety, and posttraumatic stress disorder (PTSD). Clinical data establish that the prevalence of any of these 3 diagnoses complicates the treatment of TBI regardless of whether the diagnosis was pre-existing or occurred because of the TBI, such that prognosis and recovery are negatively impacted. Despite this evidence, psychological assessment is not a first line step in the approach to TBI. The purpose of this research was to assess the prevalence of psychological screening among TBI patients for depression, anxiety, and PTSD to enable conclusions about the current standard of care in TBI management. Meta-analysis of peer reviewed journals on TBI management was used to determine if there was considerable evidence to support that depression, anxiety, and PTSD were being addressed as the standard of care in TBI management. Mean analysis of literature search results established that there was not considerable evidence to support a conclusion that depression, anxiety, and PTSD assessment were standard of care in TBI management. Among the recommendations resulting from this finding were for additional studies on TBI points of care to determine how mental health is currently being managed among TBI patients, and for a change in current TBI treatment protocols to incorporate mental health assessment as part of overall TBI management. If these, and the remaining recommendations, were implemented, it was affirmed that these would have a positive social impact resulting in improved patient outcomes, decreased healthcare costs, and better healthcare delivery for TBI patients.

In the late 90’s, emerging evidence revealed that the brain is insulin-sensitive, highlighted by broad expression of brain-specific insulin receptors and reports of circulating brain insulin. Contemporary literature robustly supports the role of insulin signaling in normal brain function and suggests that insulin-related processes diminish with aging, evidenced by decreased signaling markers, reduced insulin receptor density, and lower levels of insulin transport across the blood-brain barrier. In the context of pathological cognitive decline, clinical trials using intranasal insulin delivery have reported positive outcomes on memory and learning in patients with mild cognitive decline or early-stage Alzheimer’s disease. However, while the importance of insulin and its related actions in the brain are robustly supported, the distinct mechanisms and pathways that mediate these effects remain unclear. To address this, I conducted a series of experiments exploring the impact of insulin on memory and learning in two models: primary hippocampal cell cultures and the Fisher 344 animal model of aging. These studies attempted to identify relationships between insulin receptor signaling, neuronal gene expression, glucose metabolism, and calcium homeostasis in the hippocampus using either expression of a constitutively active human insulin receptor or administration of intranasal insulin. The following dissertation summarizes this work and provides valuable insights into the potential pathways mediating these relationships. Of note, intranasal studies reported that insulin is able to significantly alter gene expression patterns in the hippocampus of both young and aged rats following chronic, repeated exposure to the ligand. In cell culture, constitutive insulin signaling correlated with significantly elevated neuronal glucose uptake and utilization, as well as with significant alterations in the overall expression and localization of the neuron-specific glucose transporter 3. Interestingly, continued activity of the insulin receptor did not appear to alter voltage-gated calcium channels in hippocampal neurons despite prior evidence of the ligand’s role in other calcium-related processes. The results reported in this manuscript suggest that in the brain, insulin may be involved in a myriad of complex and dynamic events dependent on numerous variables, such as age, length of the exposure, and/or the insulin formulation used. Nevertheless, this work highlights the validity of using insulin to ameliorate age-related cognitive decline and supports the need for further studies exploring alternative approaches to enhance insulin receptor signaling in the brain.

Anelosimus studiosus is a socially polyphenic spider. Individuals can be classified as social/tolerant or solitary/aggressive. These behavioral differences are associated with considerable variation in social structure. Here, we begin to examine the physiological differences that may underlie the behavioral dimorphism in this species and possible implications for the evolution of sociality. Octopamine is a neurotransmitter that has been found to elevate aggression in invertebrates. Serotonin has been shown, in some cases, to interact antagonistically with octopamine. We used High Pressure Liquid Chromatography with Electrochemical Detection to quantify levels of these neurochemicals among adult females from social (multi-female) and solitary (single-female) webs in east Tennessee. A subset of spiders was scored for individual social tendency. We found that higher octopamine levels are associated with a greater degree of aggression and intolerance, both at the individual level and the population level, while higher levels of serotonin are found in multi-female colonies and social individuals.