The purpose of this study was to determine if significant differences existed in attitudes of international students concerning college withdrawal. Data collection involved 200 freshmen international students from two universities in Texas. Two questionnaires were distributed to the students to determine attitudes toward college withdrawal. The instrument used to score the attitudes was the Purdue Master Attitude Scale. The analysis of variance was used for the statistical evaluation. The statistics indicated there was no significant differences between the students tested in the study and that the students had favorable attitudes toward college and unfavorable attitudes toward college withdrawal. Based on the findings of this study, universities should devise an extensive counseling and orientation program in order to provide students opportunities to complete their college education.

While there is currently active debate over possible therapeutic applications of marijuana and cannabis-based compounds, consistently their primary drawbacks have been the psychoactive properties, dependence, and abuse potential. Prolonged administration of ∆9-tetrahydrocannabinol (THC), the primary psychoactive constituent in marijuana, demonstrates both tolerance and physical withdrawal in both preclinical and clinical studies. Repeated THC administration also produces CB1 receptor adaptations in the form of reduced activation of receptors, along with a downregulation of membrane surface receptors, in many brain regions involved in THC-associated behaviors. The increased need for drug to maintain therapeutic effects, and a withdrawal syndrome following discontinuation of use, are common risk factors in drugs of abuse. Recently, compounds have been developed that prolong the availability of the major naturally occurring endogenous cannabinoids, anandamide (AEA) and 2-arachidonoylglycerol (2-AG), through inhibition of their catabolic breakdown by fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL), respectively. The overall objectives of this research are to elucidate the physiologic roles of these two endogenous ligands and to determine if either can produce beneficial therapeutic effects without negative cannabis-like CNS effects. Therefore, we tested the impact of acute and prolonged blockade of FAAH and MAGL on a variety of cannabinoid-mediated behaviors and on precipitated cannabinoid withdrawal. Despite that acute blockade of FAAH and MAGL produce similar efficacy in reducing nociceptive responses, and both can reduce THC-induced somatic withdrawal, sustained blockade of these enzymes leads to remarkably different adaptations in CB1 receptor functioning. Namely, prolonged elevations in brain 2-AG leads to marked antinociceptive tolerance, cross-tolerance to exogenous cannabinoid agonists, and physical dependence. In contrast, sustained elevations in brain anandamide continues to dampen pain responses without apparent signs of physical withdrawal, loss of CB1 receptor activation as measured by [35S]GTPγS, or receptor downregulation as measured by [3H]CP,55940. These results suggest that chronic 2-AG elicits greater compensatory changes in CB1 receptor functions than anandamide. With similar efficacy in most therapeutic endpoints tested, and evidence of reduced impact on long-term function of the endocannabinoid system, these results distinguish FAAH as a more promising therapeutic target to treat pain and other conditions than MAGL.

Opioids are used routinely in the pediatric intensive care population for analgesia, sedation, blunting of physiologic responses to stress, and safety. In children, physical dependence may occur in as little as two to three days of continuous opioid therapy. Once the child no longer needs the opioid, the medications are reduced over time. A review of the literature revealed that the majority of the published studies used either a neonatal opioid assessment tool or no assessment tool. A subsequent international survey of pediatric providers found a wide range of opioid tapering practices and sporadic use of opioid withdrawal instruments to guide practice. Since tapering routines vary among practitioners, it is not uncommon to see signs and symptoms of opioid withdrawal. A prospective, descriptive study was conducted to describe the frequency of opioid withdrawal signs and symptoms and to identify factors associated with these opioid withdrawal signs and symptoms. The sample of 25 was drawn from all patients, ages 2 weeks to 21 years admitted to the Children’s Hospital of Richmond Pediatric Intensive Care Unit (PICU) and who have received continuous infusion or scheduled opioids for at least 5 days. Data collected included: opioid withdrawal score (WAT-1), opioid taper rate (total dose of opioid per day in morphine equivalents per kilogram [MEK]), pretaper peak MEK, pretaper cumulative MEK, number of days of opioid exposure prior to taper, and age. Out of 26 enrolled participants, only 9 (45%) had opioid withdrawal on any given day. In addition, there was limited variability in WAT-1 scores. The most common symptoms notes were diarrhea, vomit, sweat, and fever. For optimal opioid withdrawal assessments, clinicians should use a validated instrument such as the WAT-1 to measure for signs and symptoms of opioid withdrawal. Further research is indicated to examine risk factors for opioid withdrawal in children.

The effects of cannabinoids in reducing somatic signs of opioid withdrawal have been known for some time. In morphine dependent rodents, opioid withdrawal following precipitation with the mu opioid antagonist naloxone elicits robust withdrawal behaviors including jumps, paw flutters, head shakes, diarrhea and weight loss. Delta-9-tetrahydrocannabinol has been shown to reduce this opioid withdrawal in mice via activation of the cannabinoid type-1 (CB1) receptor and recently it has been shown that inhibition of the catabolic enzymes for endocannabinoids also reduce somatic signs of opioid withdrawal. Specifically, inhibition the enzyme fatty acid amide hydrolase (FAAH), the catabolic enzyme for the endocannabinoid N-arachidonoylethanolamide (AEA; anandamide) or inhibition of the enzyme monoacylglycerol lipase (MAGL), the catabolic enzyme for the endocannabinoid 2-arachindonoylglycerol (2-AG) has been shown to reduce opioid withdrawal in mice. However, FAAH inhibition only reduced a subset of withdrawal signs in mice and full MAGL inhibition which maximally reduced somatic withdrawal signs has been shown to produce THC-like effects and dependence potential. Additionally, the effects of endocannabinoid catabolic inhibitors on other aspects of withdrawal, such as the negative motivational effects, are not known. The objectives of this dissertation were to 1) assess the efficacy of dual inhibition of FAAH and MAGL on somatic signs of opioid withdrawal and 2) determine whether these treatments would produce cannabimimetic effects (hypomotility, catalepsy, antinociception and hypothermia); 3) develop other behavioral assays of opioid withdrawal; and 4) determine if endocannabinoid catabolic inhibitors would reduce the acquisition of opioid withdrawal induced conditioned place avoidance (CPA) as a measure of the negative motivational consequences of opioid withdrawal. We found that full inhibition of FAAH with the selective inhibitor PF-3845 and partial inhibition of MAGL with the selective inhibitor JZL184 reduced withdrawal-related jumps and the expression of diarrhea to a greater degree than either inhibitor alone and these effects were shown to be CB1 mediated. Additionally, we tested the novel dual FAAH/MAGL inhibitor SA-57 which has greater potency at inhibiting FAAH over MAGL and found that it similarly reduced withdrawal signs at doses that only partially elevated 2-AG while fully elevating AEA; furthermore, SA-57 did not produce cannabimimetic effects at these doses. We next assessed the effects of morphine withdrawal in five behavioral assays: marble burying, novelty-induced hypophagia, the light/dark box, a novel procedure developed to assess “escape behavior” and the CPA procedure. From these studies we selected the CPA procedure to further evaluate the effects of endocannabinoid catabolic inhibitors to determine their ability to reduce the negative motivational aspect of opioid withdrawal. We found that naloxone (0.056 mg/kg) produced robust CPA in morphine-pelleted, but not placebo-pelleted, mice and that this dose elicited minimal somatic withdrawal signs. Morphine pretreatment was shown to block withdrawal CPA and withdrawal jumping in mice while clonidine only blocked withdrawal CPA and these served as positive controls. We found that THC, JZL184, and SA-57 significantly reduced the percentage of mice that jumped during the conditioning session, demonstrating that these treatments blocked the somatic signs of withdrawal. However, none of these treatments significantly affected acquisition of the withdrawal CPA. These studies suggest that dual inhibition of FAAH/MAGL has enhanced effects on attenuating withdrawal-related jumps and diarrhea, but not the negative motivational aspects of morphine withdrawal as inferred by the Pavlovian CPA experiments.

The idea that humans and laboratory animals can become physically dependent on marijuana or its primary psychoactive constituent, delta-9-tetrahydrocannabinol (THC), is gaining acceptance. However, there are no currently approved pharmacotherapies to treat cannabinoid withdrawal. The objective of this thesis was to evaluate whether elevating endogenous anandamide levels using mice lacking fatty acid amide hydrolase (FAAH), the enzyme responsible for anandamide metabolism, would ameliorate THC dependence. Mice were treated subchronically with a low or high THC dosing regimen and challenged with the CB1 receptor antagonist, rimonabant, to precipitate withdrawal. Following subchronic THC treatment, rimonabant precipitated a significant increase in paw flutters that was dependent on THC dose. However, FAAH-/- mice displayed a similar magnitude of withdrawal responses as wild type control mice, regardless of subchronic dosing regimen. Finally, rimonabant was equipotent in precipitating withdrawal responses in both genotypes. Collectively, these results demonstrate that FAAH-/- and +/+ mice show identical THC dependence, thus arguing against the notion that elevating anandamide levels through FAAH suppression will reduce cannabinoid withdrawal.

Tobacco dependence is the leading cause of preventable death in the United States. Despite currently available smoking cessation therapies, there is a high rate of relapse in smoking among those attempting to quit. While the somatic signs of nicotine withdrawal (insomnia, increased appetite, weight gain) contribute to the continuation of smoking behavior, it has been hypothesized that the affective signs (depression, anxiety, craving, irritability) are greater motivators of relapse and continued tobacco use. There are few studies that assess the molecular and receptor-mediated mechanisms of nicotine withdrawal; therefore, our studies focus on identifying the nicotinic acetylcholine receptor (nAChR) subtypes and post-receptor calcium-dependent mechanisms involved in nicotine withdrawal behaviors. Using precipitated, spontaneous, and conditioned place aversion (CPA) models, we measured physical and affective signs of nicotine withdrawal in mice. Our data show that major nAChR subtypes have differential roles in nicotine withdrawal. Additionally, our results suggest a behavioral relevance for L-type calcium channels in physical nicotine withdrawal signs, while calcium/calmodulin dependent protein kinase II (CaMKII) appears to be involved in both physical and affective withdrawal behaviors. Additionally, we conducted biochemical studies in the ventral tegmental area (VTA) and nucleus accumbens (NAc) to examine the relationship between altered withdrawal behavioral responses and calcium-dependent molecular mechanisms that contribute to nicotine withdrawal behaviors. Our results suggest an important role for β2-containing nAChRs in nicotine-withdrawal induced decreases in CaMKII and synapsin I function in the NAc. Overall, our studies implicate a critical role for the α4α6β2* nAChR subtype in the behavioral and molecular aspects of nicotine withdrawal, thus aiding in the elucidation of nAChR subunits and mechanisms that contribute to nicotine withdrawal behaviors. The current studies are imperative for generating more successful smoking cessation therapies.

ROLE OF MAGL INHIBITION IN NICOTINE WITHDRAWAL AND REWARD. A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Virginia Commonwealth University. by Pretal Ishvarlal Patel Muldoon Director: M. Imad Damaj, PhD Professor, Department of Pharmacology and Toxicology Tobacco use is one of the leading causes of preventable deaths worldwide. Nicotine, the main psychoactive component of tobacco, sustains and initiates tobacco addiction. Cessation of nicotine induces a dependence withdrawal syndrome. Recent in vivo studies indicate that the endocannabinoid (EC) system modulates both nicotine reward and withdrawal. The purpose of this proposal is to investigate the role of enhancing endogenous 2-arachidonoylglycerol (2-AG) and by blocking its degradative enzyme, monoacylglycerol lipase (MAGL) enzyme, in nicotine reward and dependence. The selective MAGL inhibitor JZL184 dose-dependently reduced both precipitated and spontaneous somatic and aversive withdrawal signs in mice. These effects were blocked by rimonabant indicating a CB1 receptor mechanism. Furthermore, repeated administration of JZL184 for 6 days did not produce tolerance to the alleviation of withdrawal and the treatment did not induce alterations in CB1 receptor levels or receptor-mediated G-protein activity in various brain regions. In addition, a decrease in 2-AG levels was found in the nucleus accumbens in nicotine-dependent mice undergoing precipitated withdrawal, suggesting that a dysregulation of this EC signaling system occurs during nicotine withdrawal. Lastly, we tested the effectiveness of a combination of low-dose JZL184 and high dose of the FAAH inhibitor PF-3845 on spontaneous nicotine withdrawal. Indeed, the combination of low-dose JZL184 and PF-3845 significantly attenuated nicotine spontaneous withdrawal signs. MAGL inhibition by JZL184 dose-dependently caused a significant blockade of nicotine reward as measured in the mouse conditioned place preference (CPP). In contrast to withdrawal, JZL184’s effect on nicotine CPP was not CB1 mediated. In addition, JZL184 treatment did not cause significant alterations in CB1 receptor levels or receptor-mediated G-protein activity in several brain regions involved in nicotine reward. The effects of JZL184 on nicotine CPP was selective since the drug failed to alter food-induced CPP and LiCl-induced conditioned place aversion in the mouse. Interestingly, active doses of JZL184 did not only cause an increases in 2-AG levels but also induced a concomitant decrease in arachidonic acid (AA) levels in various brain regions suggesting an AA cascade dependent-mechanism. In line of these changes, a cox-2 inhibitor, valdecoxib, dose-dependently blocked nicotine preference.

Transdermal nicotine (TN) is a smoking cessation pharmacotherapy thought to work by suppressing tobacco/nicotine withdrawal and reducing the effect of a concurrently smoked tobacco cigarette. Clinical trials suggest that TN may be less efficacious for women. This study explored the possibility of gender differences in response to transdermal nicotine in 54 women and 70 men. Participants completed four within-subject, double-blind, randomized sessions corresponding to 0, 7, 14, and 21 mg TN and 4-hrs after TN application smoked an own-brand cigarette. Prior to session onset participants completed ≥ 8 hours of verified tobacco cigarette abstinence (i.e., expired air carbon monoxide levels ≤ 10 ppm). Subjective and physiological measures were administered throughout each session, and cognitive performance and smoking behavior were assessed at time points related to the smoking opportunity.Results revealed that there were few significant effects involving the gender factor across withdrawal suppression and concurrent smoking outcomes (13 significant gender-related effects out of 338 possible; 3.9%). Women were more sensitive to some of the direct effects of nicotine in the 21 mg TN condition (e.g., increased ratings of "Nauseous"). However, for women and men TN suppressed some of the signs and symptoms of withdrawal and attenuated smoking-related increases in heart rate and subjective effects that might be indicative of the positive reinforcing properties of smoking (e.g., "Was the cigarette satisfying?"). In addition, for women and men, TN did not attenuate properties of smoking that might be negatively reinforcing (e.g., smoking- induced reductions in withdrawal symptoms). Thus, although this study does not shed light on clinical observations that TN is less effective for women, results suggest that NRT might be more efficacious if combined with other interventions that supplement the withdrawal suppressing effects of TN and reduce the negative reinforcing qualities of smoking.

While caffeine withdrawal has been well-characterized, research on caffeine intake and factors associated with withdrawal has been limited. The present study examined prevalence rates of caffeine use and identified psychosocial factors associated with having caffeine withdrawal headaches (CWH). Participants were N = 1,989 college freshmen who participated in the 2011 Spit for Science project. Caffeine use was reported by 80% of the sample. Females were more likely than males to consume caffeine, and soda was the primary source of caffeine for both genders. As hypothesized, daily caffeine users were more likely to report CWH than non-daily users. When multivariable analyses examined other variables identified through univariable analyses, the most parsimonious model for distinguishing between those with and without CWH included the following set of predictor variables: daily caffeine use; female; non-white minority; peers with alcohol problems; greater neuroticism, and those reporting maternal depression or anxiety.

Master of Science / Department of Animal Sciences and Industry / Joel DeRouchey / Thirteen experiments using a total of 7,589 nursery and finishing pigs were conducted to evaluate the effects of deoxynivalenol (DON), feed additives and processing conditions on nursery pig growth performance. In addition, feed withdrawal and diet blending were evaluated in finishing pigs. Experiment 1 tested 3 feed additives in DON-contaminated diets with only Defusion Plus improving performance. Experiment 2 evaluated Biofix in both low- and high-DON diets and showed no effects on growth. Experiments 3 and 4 further evaluated levels of Defusion and the effects of pelleting and supplemental nutrients in DON-contaminated diets. Defusion improved growth in low-DON diets, but had variable effects in high DON diets. Pelleting DON-contaminated diets resulted in comparable growth to pigs fed positive control diets in meal form. In Exp. 5 and 6, pilot studies evaluated DON-detoxification using sodium metabisulfite (SMB) with hydrothermal treatment in both an autoclave and a pellet mill. These conditions reduced analyzed DON by as much as 89 and 75% for the autoclave and pellet mill, respectively. In Exp. 7 and 8, pelleting DON-contaminated diets with SMB improved growth. Experiments 9 and 10 evaluated feed-withdrawal time on carcass composition and economic returns. These experiments showed that pre-slaughter fasting for up to 36 h prior can be used to avoid weight discounts in heavyweight pigs without negatively impacting carcass composition and maintaining overall revenue. However, these advantages come with a potential reduction in carcass weight and increased incidence of leaking ingesta, which can result in condemned heads. Experiments 11, 12, and 13 compared phase-feeding to blending diets using an automated feed delivery system. These studies showed that corn-supplement blending is not economical and feeding diets blended to a Lys curve results in lower feed costs compared to phase-feeding, but due to reductions in growth and carcass weight, these savings do not translate into higher income over feed cost. Finally, Exp. 13 showed that over- and under-budgeting situations do not significantly influence overall returns, but pigs fed under-budgeted diets performed more closely to those fed correctly estimated feed budgets.