The role of dopamine in alcohol self-administration in humans: Individual differences

Objective: To clarify dopamine's role in alcohol self-administration in a heterogeneous sample of drinkers using acute phenylalanine/tyrosine depletion (APTD). Methods: Sixteen men with variable drinking histories were characterized on their ethanol-induced cardiac response, a marker previously proposed to index dopamine system reactivity and vulnerability to alcohol abuse. During separate sessions participants were administered (i) a nutritionally balanced (BAL) amino acid (AA) mixture, (ii) a mixture lacking the dopamine precursors, phenylalanine and tyrosine, and (iii) APTD followed by the dopamine precursor, l-DOPA. Five hours after AA administration, participants could earn units of alcohol using a progressive ratio breakpoint task. Results: Alcohol self-administration was reduced in the APTD and APTD + l-DOPA conditions relative to the BAL condition. In both cases the changes were predicted by ethanol-induced cardiac change. Conclusions: The motivation to drink is likely regulated by more than one neurobiological mechanism. Individual differences in cardiac responsivity to ethanol might provide a peripheral marker of responsiveness to pharmacological manipulations of dopamine.     

广州市女性美容心理动机研究

目的 了解当代女性美容心理动机.方法 自编女性美容心理动机问卷,随机抽取300名女性进行调查.结果 女性美容心理动机主要分为完美性动机、自卑与虚荣动机、从众与攀比动机以及目的性动机4种,4种动机中女性更倾向于完美性动机,最弱的是自卑与虚荣动机;年龄对女性动机有着显著影响(P＜0.01),总的来说,低年龄组的4种动机水平较高,随着年龄增大而降低,并达到显著水平;已婚组与未婚组的从众与攀比心理动机差异有统计学意义(F=4.026,P＜ 0.01),而且,已婚组在目的性动机因子上得分与未婚有男友组差异有统计学意义(F=2.356,P＜ 0.05).结论 应该正确引导女性美容心理动机,矫正美容消费心理等.     

Energy regulatory signals and food reward

The hormones insulin, leptin, and ghrelin have been demonstrated to act in the central nervous system (CNS) as regulators of energy homeostasis, acting at medial hypothalamic sites. Here, we summarize research demonstrating that, in addition to direct homeostatic actions at the hypothalamus, CNS circuitry that subserves reward and is also a direct and indirect target for the action of these endocrine regulators of energy homeostasis. Specifically, insulin and leptin can decrease food reward behaviors and modulate the function of neurotransmitter systems and neural circuitry that mediate food reward, the midbrain dopamine (DA) and opioidergic pathways. Ghrelin can increase food reward behaviors, and support midbrain DA neuronal function. We summarize discussion of behavioral, systems, and cellular evidence in support of the contributions of reward circuitry to the homeostatic roles of these hormones in the CNS. The understanding of neuroendocrine modulation of food reward, as well as food reward modulation by diet and obesity, may point to new directions for therapeutic approaches to overeating or eating disorders.     

Knowledge, attitudes, technical competence, and blood glucose control of Type 1 diabetic patients during and after an education programme

Thirty-one Type 1 diabetic patients entered a 12-month education programme in which attitudes to diabetes, knowledge of diabetes, and technical competence were assessed using questionnaires and practical tests. A closely matched group of 25 control patients continued to receive routine clinic care. Patients completing the education programme showed improved blood glucose control (HbA1 decreased from 11.8 +/- 0.4% to 10.5 +/- 0.3%, mean +/- SE, p less than 0.01), whereas blood glucose control was not altered in the control group (HbA1 11.8 +/- 0.5% before and 11.6 +/- 0.4% after 12 months). Patients completing the education programme also showed greater knowledge (p less than 0.001), more favourable attitudes (p less than 0.03), and increased competence in technical skills (p less than 0.02) compared with the control group. Six months after completing the programme blood glucose control deteriorated (HbA1 11.0 +/- 0.4%, p less than 0.05), although knowledge, attitudes, and technical competence were unchanged. This might reflect the withdrawal of extrinsic motivation and attention provided during the programme. Thus consideration should be given to development of the patient's intrinsic motivation to prolong the benefits of diabetes education programmes.     

The adenosine A<Subscript>2A</Subscript> antagonist MSX-3 reverses the effects of the dopamine antagonist haloperidol on effort-related decision making in a T-maze cost/benefit procedure

Rationale  Mesolimbic dopamine (DA) is a critical component of the brain circuitry regulating behavioral activation and effort-related processes. Research involving choice tasks has shown that rats with impaired DA transmission reallocate their instrumental behavior away from food-reinforced tasks with high response requirements and instead select less effortful food-seeking behaviors. Objective  Previous work showed that adenosine A_2A antagonism can reverse the effects of the DA antagonist haloperidol in an operant task that assesses effort-related choice. The present work used a T-maze choice procedure to assess the effects of adenosine A_2A and A₁ antagonism. Materials and methods  With this task, the two arms of the maze have different reinforcement densities (four vs. two food pellets), and a vertical 44 cm barrier is positioned in the arm with the higher density, presenting the animal with an effort-related challenge. Untreated rats strongly prefer the arm with the high density of food reward and climb the barrier in order to obtain the food. Results  Haloperidol produced a dose-related (0.05–0.15 mg/kg i.p.) reduction in the number of trials in which the rats chose the high-barrier arm. Co-administration of the adenosine A_2A receptor antagonist MSX-3 (0.75, 1.5, and 3.0 mg/kg i.p.), but not the A₁ antagonist 8-cyclopentyl-1,3-dipropylxanthine (0.75, 1.5, and 3.0 mg/kg i.p.), reversed the effects of haloperidol on effort-related choice and latency. Conclusions  Adenosine A_2A and D2 receptors interact to regulate effort-related decision making, which may have implications for the treatment of psychiatric symptoms such as psychomotor slowing or anergia that can be observed in depression, parkinsonism, and other disorders.     

The relationship between motivational structure,sense of control,intrinsic motivation and university students' alcohol consumption

The aim of this study was to determine how sense of control and intrinsic motivation are related to university students' motivational structure and alcohol consumption. Participants were 94 university students who completed the Personal Concerns Inventory, Shapiro Control Inventory, Helplessness Questionnaire, Intrinsic–Extrinsic Aspirations Scale, and Alcohol Use Questionnaire. Results showed that sense of control and intrinsic motivation were positively correlated with adaptive motivation and negatively correlated with alcohol consumption. Mediational analyses indicated that adaptive motivation fully mediated the relationship between sense of control/intrinsic motivation and alcohol consumption.     

MSI-1436 reduces acute food intake without affecting dopamine transporter activity

Many therapies designed to reduce food intake and body weight act, in part, by blocking the dopamine transporter (DAT) — a protein responsible for clearing extracellular dopamine (DA) after release thereby terminating its action. Here, we found that a single injection of the drug trodusquemine (MSI-1436) decreased food intake in rats. To assess the effects of MSI-1436 on DAT function, fast-scan cyclic voltammetry was used to measure DA concentration changes in the ventral striatum. DA release was evoked by electrical stimulation of the ventral tegmental area every 5 min. After 3 baseline measurements, rats were injected with MSI-1436 (10 mg/kg), the known DAT blocker bupropion (80 mg/kg) or saline and evoked DA release and reuptake were monitored for an additional hour. Neither saline nor MSI-1436 caused a significant change in the magnitude of evoked release from baseline values whereas bupropion caused a significant increase. In addition, neither saline nor MSI-1436 significantly increased DA decay rates while such an increase was observed with bupropion. Thus, over a time course when MSI-1436 suppresses food intake it does not affect DAT function. The results support MSI-1436 as an anti-obesity treatment which spares DAT.     

Dopamine receptors in the ventral tegmental area affect motor, but not motivational or reflexive, components of copulation in male rats

Microinjection of apomorphine into the ventral tegmental area (VTA) of male rats was previously shown to delay the onset of copulation and slow its rate, presumably by stimulating impulse-regulating autoreceptors on cell bodies of the A10 mesocorticolimbic dopamine tract. Such stimulation would be expected to slow the firing rate of these neurons and, thereby, to impair locomotion and/or motivational processes. The present experiments tested whether the delayed onset and slowed rate of copulation were related to deficits in motor performance, sexual motivation, and/or genital reflexes. In X-maze tests the speed of running to all 4 goal boxes was slowed; however, the percentage of trials on which the male chose the female's goal box was not decreased. Examination of videotaped copulation tests revealed that the male showed fewer complete copulatory behaviors (mounts, intromissions, and ejaculations), but more misdirected or incomplete copulatory attempts after apomorphine in the VTA. There were also fewer scores of active, as opposed to inactive, behaviors, and the onset and rate of copulation were slowed. The total number of female directed behaviors was not different in apomorphine tests, compared to vehicle. Finally, tests of ex copula genital reflexes revealed no significant effects of apomorphine in the VTA on erections, penile movements, or seminal emissions. These data suggest a role of the VTA in the motor aspects and/or sensorimotor integration of copulation. Sexual motivation and ex copula genital reflexes appeared to be unaffected by apomorphine in the VTA.     

Coaching older adults discharged home from the emergency department: The role of competence and emotion in following up with outpatient clinicians

ObjectiveMotivating older adults to follow up with an outpatient clinician after discharge from emergency departments (ED) is beneficial yet challenging. We aimed to answer whether psychological needs for motivation and discrete emotions observed by care transition coaches would predict this behavioral outcome.MethodsCommunity-dwelling older adults following ED discharge were recruited from three EDs in two U.S. states. We examined home visit notes documented by coaches (N = 725). Retrospective chart reviews of medical records tracked participants’ health care utilization for 30 days.ResultsObserved knowledge-based competence predicted higher likelihood of outpatient follow-up within 30 days, while observed sadness predicted a lower likelihood of follow-up within seven days following discharge. Moreover, participants who demonstrated happiness were marginally more likely to have an in-person follow-up within seven days, and those who demonstrated knowledge-based competence were more likely to have an electronic follow-up within 30 days.ConclusionsKnowledge-based competence and emotions, as observed and documented in coach notes, can predict older adults’ subsequent outpatient follow-up following their ED-discharge.Practice implicationsIntervention programs might encourage coaches to check knowledge-based competence and to observe emotions in addition to delivering the content. Coaches could also customize strategies for patients with different recommended timeframes of follow-up.