601 research outputs found

    Implementation of Vitamin D Screening and Planned Intervention of Supplementation for Deficient Collegiate Athletes of the Rio Grande Valley

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    In the past decade, studies on vitamin D levels and relationships to orthopaedic patients have increased exponentially worldwide. Journals have established risk factors, proper assessment of vitamin D levels, supplementation standards, and dependent variables that effect prevalence.1 More specifically, many vitamin D studies in the field of orthopaedics and sports medicine have been conducted by analyzing NFL teams and NCAA Division I athletes and dividing the cohorts into player parameters such as age, BMI, race, team position, and supplement type. The results of these studies concluded that there is a large prevalence of vitamin D deficiency amongst athletes and an even higher abnormality of serum vitamin D levels in races with darker skin tones.3 Studies also have been conducted on the benefits of vitamin D and calcium supplementation to prevent over-use injuries like stress fractures.4 An example would be a study showing a 20% lower incidence of stress fractures in navy recruits in a 24-month period.5 But despite such a high level of interest in analyses of vitamin D in athletes, the prevalence of hypovitaminosis D and its influence in overuse injuries like stress fractures within the population of collegiate athletes in the Rio Grande Valley has not yet been investigated

    Drug Predictive Cues Activate Aversion-Sensitive Striatal Neurons That Encode Drug Seeking

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    Drug-associated cues have profound effects on an addict’s emotional state and drug-seeking behavior. Although this influence must involve the motivational neural system that initiates and encodes the drug-seeking act, surprisingly little is known about the nature of such physiological events and their motivational consequences. Three experiments investigated the effect of a cocaine-predictive stimulus on dopamine signaling, neuronal activity, and reinstatement of cocaine seeking. In all experiments, rats were divided into two groups (paired and unpaired), and trained to self-administer cocaine in the presence of a tone that signaled the immediate availability of the drug. For rats in the paired group, self-administration sessions were preceded by a taste cue that signaled delayed drug availability. Assessments of hedonic responses indicated that this delay cue became aversive during training. Both the self-administration behavior and the immediate cue were subsequently extinguished in the absence of cocaine. After extinction of self-administration behavior, the presentation of the aversive delay cue reinstated drug seeking. In vivo electrophysiology and voltammetry recordings in the nucleus accumbens measured the neural responses to both the delay and immediate drug cues after extinction. Interestingly, the presentation of the delay cue simultaneously decreased dopamine signaling and increased excitatory encoding of the immediate cue. Most importantly, the delay cue selectively enhanced the baseline activity of neurons that would later encode drug seeking. Together these observations reveal how cocaine cues can modulate not only affective state, but also the neurochemical and downstream neurophysiological environment of striatal circuits in a manner that promotes drug seeking

    Aversive Stimuli Drive Drug Seeking in a State of Low Dopamine Tone

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    Background Stressors negatively impact emotional state and drive drug seeking, in part, by modulating the activity of the mesolimbic dopamine system. Unfortunately, the rapid regulation of dopamine signaling by the aversive stimuli that cause drug seeking is not well characterized. In a series of experiments, we scrutinized the subsecond regulation of dopamine signaling by the aversive stimulus, quinine, and tested its ability to cause cocaine seeking. Additionally, we examined the midbrain regulation of both dopamine signaling and cocaine seeking by the stress-sensitive peptide, corticotropin releasing factor (CRF). Methods Combining fast-scan cyclic voltammetry with behavioral pharmacology, we examined the effect of intraoral quinine administration on nucleus accumbens dopamine signaling and hedonic expression in 21 male Sprague-Dawley rats. We tested the role of CRF in modulating aversion-induced changes in dopamine concentration and cocaine seeking by bilaterally infusing the CRF antagonist, CP-376395, into the ventral tegmental area (VTA). Results We found that quinine rapidly reduced dopamine signaling on two distinct time scales. We determined that CRF acted in the VTA to mediate this reduction on only one of these time scales. Further, we found that the reduction of dopamine tone and quinine-induced cocaine seeking were eliminated by blocking the actions of CRF in the VTA during the experience of the aversive stimulus. Conclusions These data demonstrate that stress-induced drug seeking can occur in a terminal environment of low dopamine tone that is dependent on a CRF-induced decrease in midbrain dopamine activity

    Health problems and help-seeking activities of methadone maintenance clients at Auckland Methadone Service (AMS): potential for community pharmacy service expansion?

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    BACKGROUND: In general the health of methadone clients has been found to be poorer than that of the general population. In New Zealand specialist drug services are not funded to provide primary healthcare services. Many health conditions could potentially be managed by community pharmacists who have frequent contact with this client group. This study sought to explore the health problems suffered by methadone clients, who they sought help from, and the potential for greater involvement of pharmacists. METHODS: Self-completion questionnaire of methadone maintenance clients managed in specialist care in Auckland, New Zealand. RESULTS: The most common health problem experienced by these clients in the past three months was sweating (70.0%), and more than half of the respondents also reported experiencing headache, fatigue and depression. The least frequently experienced conditions were hay fever (12.9%) and abscesses (12.1%). Respondents indicated that the top three choices from whom they would seek help were GP (56.7%), the client's partner (31.6%) and community pharmacists (27.9%). Barriers to seeking help from pharmacists included issues around cost, perceptions of pharmacist knowledge and skills, privacy and confidentiality. CONCLUSION: Methadone clients in this study indicated that they suffered a number of general health problems, and in many cases were likely to seek help from a GP or their own partner, before seeking help from pharmacists. However, for over one quarter of respondents the pharmacist was in the top three from whom they would seek advice. Any barriers towards consulting pharmacists, in the main seem to be resolvable

    Corticosterone Regulates Both Naturally Occurring and Cocaine‐Induced Dopamine Signaling by Selectively Decreasing Dopamine Uptake

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    Stressful and aversive events promote maladaptive reward‐seeking behaviors such as drug addiction by acting, in part, on the mesolimbic dopamine system. Using animal models, data from our laboratory and others show that stress and cocaine can interact to produce a synergistic effect on reward circuitry. This effect is also observed when the stress hormone corticosterone is administered directly into the nucleus accumbens (NAc), indicating that glucocorticoids act locally in dopamine terminal regions to enhance cocaine\u27s effects on dopamine signaling. However, prior studies in behaving animals have not provided mechanistic insight. Using fast‐scan cyclic voltammetry, we examined the effect of systemic corticosterone on spontaneous dopamine release events (transients) in the NAc core and shell in behaving rats. A physiologically relevant systemic injection of corticosterone (2 mg/kg i.p.) induced an increase in dopamine transient amplitude and duration (both voltammetric measures sensitive to decreases in dopamine clearance), but had no effect on the frequency of transient release events. This effect was compounded by cocaine (2.5 mg/kg i.p.). However, a second experiment indicated that the same injection of corticosterone had no detectable effect on the dopaminergic encoding of a palatable natural reward (saccharin). Taken together, these results suggest that corticosterone interferes with naturally occurring dopamine uptake locally, and this effect is a critical determinant of dopamine concentration specifically in situations in which the dopamine transporter is pharmacologically blocked by cocaine

    Effect of Whole Body Vibration on Delayed-onset Muscle Soreness

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    The purpose of this study was to examine the effects of whole body vibration (WBV) on delayed-onset muscle soreness, specifically pain ratings, sit-and-reach scores, and vertical jump scores. Participants in the study were 20 (10 male; 10 female) healthy, college-aged students (20.85 1.81 years). All students completed an IRB informed consent document and health history questionnaire to determine eligibility. Participants were randomly assigned to a treatment or control group. For each participant, delayed-onset muscle soreness was induced via weighted lunges. Subsequently, the experimental treatment group underwent 10min. WBV before and after assessment for five consecutive days while the control group walked on a treadmill before and after each assessment. Assessment included visual analog pain rating, flexibility, and vertical jump measures. No significant results were found between the control and experimental groups regarding pain ratings, sit-and-reach scores, and vertical jump scores. While not statiSchool of Teaching and Curriculum Leadershi

    Engineering Design Challenge

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    Corticosterone Acts in the Nucleus Accumbens to Enhance Dopamine Signaling and Potentiate Reinstatement of Cocaine Seeking

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    Stressful life events are important contributors to relapse in recovering cocaine addicts, but the mechanisms by which they influence motivational systems are poorly understood. Studies suggest that stress may “set the stage” for relapse by increasing the sensitivity of brain reward circuits to drug-associated stimuli. We examined the effects of stress and corticosterone on behavioral and neurochemical responses of rats to a cocaine prime after cocaine self-administration and extinction. Exposure of rats to acute electric footshock stress did not by itself reinstate drug-seeking behavior but potentiated reinstatement in response to a subthreshold dose of cocaine. This effect of stress was not observed in adrenalectomized animals, and was reproduced in nonstressed animals by administration of corticosterone at a dose that reproduced stress-induced plasma levels. Pretreatment with the glucocorticoid receptor antagonist RU38486 did not block the corticosterone effect. Corticosterone potentiated cocaine-induced increases in extracellular dopamine in the nucleus accumbens (NAc), and pharmacological blockade of NAc dopamine receptors blocked corticosterone-induced potentiation of reinstatement. Intra-accumbens administration of corticosterone reproduced the behavioral effects of stress and systemic corticosterone. Corticosterone treatment acutely decreased NAc dopamine clearance measured by fast-scan cyclic voltammetry, suggesting that inhibition of uptake2-mediated dopamine clearance may underlie corticosterone effects. Consistent with this hypothesis, intra-accumbens administration of the uptake2 inhibitor normetanephrine potentiated cocaine-induced reinstatement. Expression of organic cation transporter 3, a corticosterone-sensitive uptake2 transporter, was detected on NAc neurons. These findings reveal a novel mechanism by which stress hormones can rapidly regulate dopamine signaling and contribute to the impact of stress on drug intake
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