Effect of aerobic exercise on behavioral and neuroendocrine responses to meta-chlorophenylpiperazine and to ipsapirone in untrained healthy subjects

Exercise as Treatment for "Stress-Related" Mental Disorders

The beneficial impact of physical activity on preventing and treating mental disorders has captured growing (research) interest. This article aims to provide a concise overview of essential evidence regarding the effectiveness and underlying mechanisms of physical activity for individuals with mental disorders clustered as "stress-related" conditions. Empirical findings (e.g., longitudinalprospective studies, interventional randomized-controlled-trials, reviews, meta-analyses) regarding the effects of physical activity in the prevention and treatment of stress-related mental disorders are summarized. Furthermore, potential mechanisms underlying these effects are discussed, and recommendations regarding the use of physical activity are outlined. The majority of studies indicate good efficacy of physical activity in prospectively lowering the risk for the incidence of subsequent stress-related mental disorders as well as in the treatment of manifest disorders. Most evidence targets unipolar depressive disorder and, secondly, anxiety disorders. Research regarding posttraumatic stress disorder, obsessive-compulsive disorders, and somatoform disorders is promising but scarce. Physical activity seems to be useful as a stand-alone-treatment as well as in combination with other psychotherapeutic or pharmacological treatments. Multiple intertwined physiological, psychological, and social mechanisms are assumed to mediate the beneficial effects. Recommendations regarding physical activity can orientate on official guidelines but should consider the individual needs and circumstances of each subject. In summary, physical activity seems to be effective in the prevention and treatment of stressrelated mental disorders and, therefore, should be fostered in healthcare-settings. Future studies are needed to clarify partly inconsistent patterns of results and to close research gaps, e.g., concerning somatoform disorders.

Exercise reduces the anxiogenic effects of meta-chlorophenylpiperazine: The role of 5-HT2C receptors in the bed nucleus of the stria terminalis

Introduction

Two weeks of voluntary exercise in group-housed mice produces a reduction in anxiety-like behaviors across a number of different measures, including a reduction in the anxiety levels typically produced by the anxiogenic serotonergic drug m-chlorophenylpiperazine (mCPP), an agonist at 5-HT2C/2b receptors. We have previously demonstrated that 2-weeks of voluntary exercise blunted the anxiogenic effects of systemic mCPP, and we have also shown that mCPP infused into the bed nucleus of the stria terminalis (BNST) is anxiogenic. Here we follow up on these reports.

Methods

In Experiment 1 we infused several doses of mCPP into the BNST with or without the 5-HT2C antagonist SB242084. In Experiment 2, we administered mCPP into amygdala subregions and the dorsal hippocampus to investigate site specificity. In Experiment 4 we lesioned the BNST and subsequently infused mCPP systemically, and in Experiment 4 we used RNAscope^® to assess BNST 5-HT2C transcripts following wheel running.

Results

BNST mCPP infusion increased acoustic startle responding, which was by 5-HT2C antagonism, while neither mCPP infused into the amygdala nor hippocampus was anxiogenic. Lesions of the BNST prevented the anxiogenic effect of systemically administered mCPP. Lastly, exercise reduced 5-HT2C transcripts in the BNST.

Discussion

These results suggest that the BNST is a critical site of action for the effects of exercise on mCPP. Together these data suggest that exercise may reduce 5-HT2C receptor function in the BNST, which may, in part, explain some of the anxiolytic effects associated with wheel running.

Physical activity and depression: Towards understanding the antidepressant mechanisms of physical activity

Physical activity can treat and prevent depressive symptoms, but its antidepressant mechanisms are yet to be established. In this review, we comprehensively assess key biological and psychosocial mechanisms through which physical activity exerts antidepressant effects, with a particular focus on exercise. Exercise, a subset of physical activity, influences a range of biological and psychosocial processes also implicated in the pathophysiology of depression. We focus on the capacity for exercise to elicit changes in neuroplasticity, inflammation, oxidative stress, the endocrine system, self-esteem, social support and self-efficacy. We also discuss how a better understanding of these mechanisms can inform the way we design and implement exercise-based interventions to maximise their antidepressant effects on an individual basis. We conclude by presenting a conceptual framework of the key biological and psychosocial mechanisms underlying the relationship between physical activity and depressive symptoms, and the moderators and confounders that may influence it.

Exercise decreases defensive responses to unpredictable, but not predictable, threat

BACKGROUND

Research supports the anxiolytic effect of exercise, but the mechanism underlying this effect is unclear. This study examines the influence of exercise in healthy controls on two distinct defensive states implicated in anxiety disorders: fear, a phasic response to a predictable threat, and anxiety, a sustained response to an unpredictable threat.

METHODS

Thirty-four healthy volunteers (17 male, age M = 26.18, SD = 5.6) participated in sessions of exercise (biking at 60-70% of heart rate reserve) and control (biking at 10-20% of heart rate reserve) activity for 30 min, separated by 1 week. Threat responses were measured by eyeblink startle and assessed with the "Neutral-Predictable-Unpredictable threat test," which includes a neutral (N) and two threat conditions, one with predictable (P) and one with unpredictable (U) shock.

RESULTS

Results show that exercise versus control activity reduces startle potentiation during unpredictable threat (P = .031), but has no effect on startle potentiation during predictable threat (P = .609).

CONCLUSIONS

These results suggest that exercise reduces defensive response to unpredictable, but not predictable, threat, a dissociation that may help inform clinical indications for this behavioral intervention, as well as provide clues to its underlying neurobehavioral mechanisms.

Physical exercise-induced fatigue: the role of serotonergic and dopaminergic systems

Brain serotonin and dopamine are neurotransmitters related to fatigue, a feeling that leads to reduced intensity or interruption of physical exercises, thereby regulating performance. The present review aims to present advances on the understanding of fatigue, which has recently been proposed as a defense mechanism instead of a “physiological failure” in the context of prolonged (aerobic) exercises. We also present recent advances on the association between serotonin, dopamine and fatigue. Experiments with rodents, which allow direct manipulation of brain serotonin and dopamine during exercise, clearly indicate that increased serotoninergic activity reduces performance, while increased dopaminergic activity is associated with increased performance. Nevertheless, experiments with humans, particularly those involving nutritional supplementation or pharmacological manipulations, have yielded conflicting results on the relationship between serotonin, dopamine and fatigue. The only clear and reproducible effect observed in humans is increased performance in hot environments after treatment with inhibitors of dopamine reuptake. Because the serotonergic and dopaminergic systems interact with each other, the serotonin-to-dopamine ratio seems to be more relevant for determining fatigue than analyzing or manipulating only one of the two transmitters. Finally, physical training protocols induce neuroplasticity, thus modulating the action of these neurotransmitters in order to improve physical performance.

Drug-induced hypothermia by 5HT1A agonists provide neuroprotection in experimental stroke: new perspectives for acute patient treatment

BACKGROUND

Drug-induced hypothermia reduces brain damage in animal stroke models and is an undiscovered potential in human stroke treatment. We studied hypothermia induced by the serotonergic agonists S14671 (1-[2-(2-thenoylamino)ethyl]-4[1-(7- methoxynaphtyl)]piperazine) and ipsapirone in a rat stroke model and in man by literature meta-analysis.

METHODS

Rats had 60 minutes of middle cerebral artery occlusion (MCAO) and then 7 days of survival. Body temperatures were monitored for 22 hours. Thirty minutes after MCAO, 1 group (n = 9) received bolus of S14671 (.75 mg/kg) and continuous infusion of .06 mg/kg hour(-1) S14671 for 20 hours. Other MCAO rats (n = 7) had bolus of ipsapirone (.75 mg/kg) and continuous infusion of .25 mg/kg hour(-1) ipsapirone for 3 hours. Controls (n = 9; n = 5) received similar amounts of vehicle as bolus and continuous infusion for 20 hours/3 hours. Additional controls of the S14761 effect in MCAO were performed as previously mentioned (n = 10) but with rats kept normothermic by a heating lamp for 22 hours. Finally, a meta-analysis of ipsapirone-induced hypothermia in man was included.

RESULTS

Infarct volumes were reduced by 50% in hypothermic rats versus controls (P < .05). S14671 rats kept normothermic did not show infarct reduction (P > .05). The body temperature after stroke was reduced 1.0-3.0°C compared with controls for 20 hours with S14671 treatment and for 6 hours with ipsapirone treatment. In humans, ipsapirone reduced temperature in average with .55 °C ranging between .1-1.4 °C.

CONCLUSIONS

5-hydroxytryptamine receptor 1A (5HT(1A)) agonists significantly reduce infarct volumes in MCAO rats primarily because of the hypothermic drug effect. 5HT(1A) agonists may be introduced to reduce body temperatures rapidly and prepare patients for further therapeutic hypothermia.

Exercise-associated changes in the corticosterone response to acute restraint stress: evidence for increased adrenal sensitivity and reduced corticosterone response duration

Exercise promotes stress resistance and is associated with reduced anxiety and reduced depression in both humans and in animal models. Despite the fact that dysfunction within the hypothalamic pituitary adrenal (HPA) axis is strongly linked to both anxiety and depressive disorders, the evidence is mixed as to how exercise alters the function of the HPA axis. Here we demonstrate that 4 weeks of voluntary wheel running was anxiolytic in C57BL/6J mice and resulted in a shorter time to peak corticosterone (CORT) and a more rapid decay of CORT following restraint stress. Wheel running was also associated with increased adrenal size and elevated CORT following systemic administration of adrenocorticotropic hormone. Finally, the HPA-axis response to peripheral or intracerebroventricular administration of dexamethasone did not suggest that wheel running increases HPA-axis negative feedback through GR-mediated mechanisms. Together these findings suggest that exercise may promote stress resilience in part by insuring a more rapid and shortened HPA response to a stressor thus affecting overall exposure to the potentially negative effects of more sustained HPA-axis activation.

Exercise affects symptom severity but not biological measures in depression and somatization - results on IL-6, neopterin, tryptophan, kynurenine and 5-HIAA

Exercise leads to symptom reduction in affective disorders and functional somatic syndromes. Biological hypotheses of underlying mechanisms include serotonergic and immunological pathways. We aimed to investigate biological features in persons with major depression and somatoform syndromes, and to analyze effects of short-term graded exercise on these parameters. Baseline values for depressive and somatoform symptoms, tryptophan, kynurenine, 5-hydroxyindoleacetic acid, neopterin and interleukin-6 were compared with those after one week of increased and one week of reduced physical activity. Thirty-eight persons with major depression, 27 persons with a minimum of 6-8 somatoform symptoms, and 48 healthy controls participated in the study. Depressive and somatoform symptoms were reduced after the active week, and an interaction pointed towards group-specific reduction of psychopathology. Participants with major depression had lower levels of kynurenine compared to controls, with intermediate concentrations in somatoform patients. There were no systematic associations of symptom improvement with biological changes. A possible limitation of the design is that a control condition with low physical activity, but no placebo condition was included. People with multiple somatoform symptoms and major depression benefit from a short and low-graded exercise intervention. These effects do not seem to be mediated by changes in serotonergic and inflammatory parameters.

5-HT2C receptors in the basolateral amygdala and dorsal striatum are a novel target for the anxiolytic and antidepressant effects of exercise

Physical activity reduces the incidence and severity of psychiatric disorders such as anxiety and depression. Similarly, voluntary wheel running produces anxiolytic- and antidepressant-like effects in rodent models. The specific neurobiological mechanisms underlying the beneficial properties of exercise, however, remain unclear. One relevant pharmacological target in the treatment of psychiatric disorders is the 5-HT(2C) receptor (5-HT(2C)R). Consistent with data demonstrating the anxiogenic consequences of 5-HT(2C)R activation in humans and rodents, we have previously reported that site-specific administration of the selective 5-HT(2C)R agonist CP-809101 in the lateral/basolateral amygdala (BLA) increases shock-elicited fear while administration of CP-809101 in the dorsal striatum (DS) interferes with shuttle box escape learning. These findings suggest that activation of 5-HT(2C)R in discrete brain regions contributes to specific anxiety- and depression-like behaviors and may indicate potential brain sites involved in the anxiolytic and antidepressant effects of exercise. The current studies tested the hypothesis that voluntary wheel running reduces the behavioral consequences of 5-HT(2C)R activation in the BLA and DS, specifically enhanced shock-elicited fear and interference with shuttle box escape learning. After 6 weeks of voluntary wheel running or sedentary conditions, the selective 5-HT(2C)R agonist CP-809101 was microinjected into either the BLA or the DS of adult Fischer 344 rats, and shock-elicited fear and shuttle box escape learning was assessed. Additionally, in-situ hybridization was used to determine if 6 weeks of voluntary exercise changed levels of 5-HT(2C)R mRNA. We found that voluntary wheel running reduced the behavioral effects of CP-809101 and reduced levels of 5-HT(2C)R mRNA in both the BLA and the DS. The current data indicate that expression of 5-HT(2C)R mRNA in discrete brain sites is sensitive to physical activity status of the organism, and implicates the 5-HT(2C)R as a target for the beneficial effects of physical activity on mental health.

Exploring exercise as an avenue for the treatment of anxiety disorders

Anxiety disorders constitute a significant public health problem. Current gold standard treatments are limited in their effectiveness, prompting the consideration of alternative approaches. In this review, we examine the evidence for exercise as an intervention for anxiety disorders. This evidence comes from population studies, studies of nonclinical anxiety reduction, as well as a limited number of studies of clinically anxious individuals. All of these studies provide converging evidence for consistent beneficial effects of exercise on anxiety, and are consistent with a variety of accounts of the mechanism of anxiety reduction with exercise. Further study of clinical populations is encouraged, as are studies of the mechanism of change of exercise interventions, which have the potential to help refine exercise intervention strategies. Likewise, studies that identify moderators of treatment efficacy will assist clinicians in deciding how and for whom to prescribe exercise.

Does physical activity reduce risk for Alzheimer's disease through interaction with the stress neuroendocrine system?

Lack of physical activity (PA) is a risk factor for Alzheimer's disease (AD), and PA interventions are believed to provide an effective non-pharmacological approach for attenuating the symptoms of this disease. However, the mechanism of action of these positive effects is currently unknown. It is possible that the benefits may be at least partially mediated by the effects on the neuroendocrine stress system. Chronic stress can lead to dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis, leading to aberrant basal and circadian patterns of cortisol secretion and a cascade of negative downstream events. These factors have been linked not only to reduced cognitive function but also increased levels of amyloid-β plaques and protein tau "tangles" (the neuropathological hallmarks of AD) in the non-demented mouse models of this disease. However, there is evidence that PA can have restorative effects on the stress neuroendocrine system and related risk factors relevant to AD. We explore the possibility that PA can positively impact upon AD by restoring normative HPA axis function, with consequent downstream effects upon underlying neuropathology and associated cognitive function. We conclude with suggestions for future research to test this hypothesis in patients with AD.

Exercise and severe depression: preliminary results of an add-on study

BACKGROUND

Physical exercise has been extensively researched as a therapeutic option for treatment of major depression.

METHODS

In a randomized controlled trial, we analyze the effects of aerobic physical exercise as an add-on strategy for treatment of severe depressed inpatients. The exercise has a "Dose" of 16.5 kcal/kg/week, three times a week during all the hospitalization.

RESULTS

Our preliminary results show that there is no significant difference in scores of Hamilton in the second week between groups (Mean[SD]=8.2[5.96] × 11.18[5.03], p=0.192). However, there is a significant reduction in Hamilton scores of patients in exercise group at discharge (Mean[SD]=5.93[4.46] × 9.45[3.56], p=0.041). Regarding Quality of Life (QoL), no significant difference were found between groups in the second week in physical domain (Mean[SD]=56.98[8.96] × 54.54[9.18], p=0.511) and psychological domain (Mean[SD]=50.88[13.88] × 42.04[12.42], p=0.106). However, there is a significant difference in psychological domain (Mean[SD]=55.88[9.92] v 41.66[13.04], p=0.004) and a trend but no statistical significance in the physical (Mean[SD]=58.80[9.14] × 52.12[8.70], p=0.07) at discharge.

LIMITATIONS

Many patients receive different treatment strategies, like ECT (1 patient at exercise group × 3 at control group). Other limitation is the small number of participants included until this moment.

CONCLUSION

Our preliminary results suggest that physical exercise could be a feasible and effective add-on strategy for treatment of severe depressed inpatients, improving their depressive symptoms and QoL.

Depression, Anxiety, and Coping in Surfers

Surfers are a heterogeneous population with a common interest in riding waves. Surfers qualitatively describe the surfing sensation as a hybrid of meditative and athletic experience. Numerous empirical studies link both meditative experience and exercise with reduced incidence of depression and anxiety; this potentially suggests that surfers may endorse fewer symptoms of either disorder. One hundred surfers (N= 100) were administered the Beck Depression Inventory-II, the Beck Anxiety Inventory, the Coping Inventory for Stressful Situations, and a demographics questionnaire. Results indicate that surfers reported significantly fewer symptoms of depression and anxiety, and employed emotion-based coping responses to stressful situations significantly less than the general populace. Surfers also employed avoidance-based coping strategies more frequently than the general populace. Future study should evaluate causal relationships between surfing and incidence of depression and anxiety.

Anxiety, Health Risk Factors, and Chronic Disease

Anxiety disorders are the most common mental health condition and frequently co-occur with a variety of health risk factors, such as physical inactivity, cigarette smoking, and alcohol consumption. As such, untreated anxiety and increased risk for engagement in these health risk habits can further increase risk for later-onset chronic disease and complications in disease management. Contemporary studies have identified unique temporal relationships between the onset of specific anxiety disorders with smoking and alcohol use disorders. Incorporating exercise with evidence-based treatments for anxiety is emerging and promising in enhancing treatments for anxiety-related conditions. Likewise, substance use treatment programs may benefit from the detection and management of anxiety. Collaborative care models for anxiety may provide the needed systems-based approach for treating anxiety more effectively in primary and specialty care medical settings. Based on a qualitative review of the literature, this article summarizes the current research on the associations between anxiety, health risk factors, and the risk for chronic diseases. The authors also offer suggestions for future research that would help in better understanding the complex relationships between the role anxiety plays in the vulnerability for and management of physical inactivity and substance use.

Growth hormone, prolactin and cortisol response to exercise in patients with depression

BACKGROUND

A blunted growth hormone and prolactin response to pharmacological stress test have previously been found in depressed patients, as well as an increased cortisol response to psychosocial stress. This study investigated these hormones in response to acute exercise using an incremental bicycle test.

METHOD

A cross-sectional comparison of cortisol, growth hormone, and prolactin in depressed (n=137) and healthy (n=44) subjects during rest and in response to an incremental bicycle test. Secondly, we tested the depressed patients again after a 4-month randomized naturalistic exercise intervention.

RESULTS

Resting plasma levels of growth hormone (GH), cortisol, or prolactin (PRL) did not differ between depressed and healthy subjects (all p-values>.12). In response to an incremental bicycle test the GH (p=.02) and cortisol (p=.05) response in depressed was different compared to healthy controls. The effect of acute exercise stress on PRL (p=.56) did not differ between depressed and healthy subjects. Apart from a decrease in GH response in the strength-training group (p=.03) the pragmatic exercise intervention did not affect resting hormonal levels, or the response to acute exercise.

CONCLUSIONS

Patients with mild to moderate depression had a different growth hormone and cortisol response to acute exercise stress compared to healthy controls. Strength training was able to reduce the growth hormone response to acute exercise stress in this patient population. Studies with more rigorous inclusion criteria and higher exercise frequencies are needed to evaluate and confirm the possible effect of exercise in depressed subjects.

The serotonin-1A receptor in anxiety disorders

The serotonin system plays an important role in the neural processing of anxiety. The involvement of the main inhibitory serotonergic receptor, the serotonin-1A (5-HT1A) subtype, in dysfunctional forms of anxiety has been supported by findings from a wide range of preclinical research and clinical trials, including treatment studies, genetic research, and neuroimaging data. The following article summarizes preclinical results with a focus on 5-HT1A receptor knockout and transgenic mice as genetic models of anxiety. Behavioral, autonomic, and endocrinological changes in these mice are reported. This article also presents genetic polymorphisms in humans associated with increased anxiety scores and pharmacological data focused on 5-HT1A receptor agonists and antagonists. Furthermore, molecular neuroimaging results are presented. Recent positron emission tomography (PET) studies have reported reduced 5-HT1A receptor binding in patients with panic disorder and social anxiety disorder, but not in posttraumatic stress disorder. In healthy subjects, increased anxiety scores might be associated with lower 5-HT1A receptor binding. This overview of preclinical and clinical data provides strong evidence for the key role of the 5-HT1A receptor in the serotonergic dysregulation of anxiety disorders.

Bi-directional modulation of bed nucleus of stria terminalis neurons by 5-HT: molecular expression and functional properties of excitatory 5-HT receptor subtypes

Activation of neurons in the anterolateral bed nucleus of the stria terminalis (BNST(ALG)) plays an important role in mediating the behavioral response to stressful and anxiogenic stimuli. Application of 5-HT elicits complex postsynaptic responses in BNST(ALG) neurons, which includes (1) membrane hyperpolarization (5-HT(Hyp)), (2) hyperpolarization followed by depolarization (5-HT(Hyp-Dep)), (3) depolarization (5-HT(Dep)) or (4) no response (5-HT(NR)). We have shown that the inhibitory response is mediated by activation of postsynaptic 5-HT(1A) receptors. Here, we used a combination of in vitro whole-cell patch-clamp recording and single cell reverse transcriptase polymerase chain reaction (RT-PCR) to determine the pharmacological properties and molecular profile of 5-HT receptor subtypes mediating the excitatory response to 5-HT in BNST(ALG) neurons. We show that the depolarizing component of both the 5-HT(Hyp/Dep) and the 5-HT(Dep) response was mediated by activation of 5-HT(2A), 5-HT(2C) and/or 5-HT(7) receptors. Single cell RT-PCR data revealed that 5-HT(7) receptors (46%) and 5-HT(1A) receptors (41%) are the most prevalent receptor subtypes expressed in BNST(ALG) neurons. Moreover, 5-HT receptor subtypes are differentially expressed in type I-III BNST(ALG) neurons. Hence, 5-HT(2C) receptors are almost exclusively expressed by type III neurons, whereas 5-HT(7) receptors are expressed by type I and II neurons, but not type III neurons. Conversely, 5-HT(2A) receptors are found predominantly in type II neurons. Finally, bi-directional modulation of individual neurons occurs only in type I and II neurons. Significantly the distribution of 5-HT receptor subtypes in BNST(ALG) neurons predicted the observed expression pattern of 5-HT responses determined pharmacologically. Together, these results suggest that 5-HT can differentially modulate the excitability of type I-III neurons, and further suggest that bi-directional modulation of BNST(ALG) neurons occurs primarily through an interplay between 5-HT(1A) and 5-HT(7) receptors. Hence, modulation of 5-HT(7) receptor activity in the BNST(ALG) may offer a novel avenue for the design of anxiolytic medications.

Anxiety-like behaviors produced by acute fluoxetine administration in male Fischer 344 rats are prevented by prior exercise

RATIONALE

Although selective 5-HT reuptake inhibitors (SSRIs) can reduce anxiety after chronic treatment, acute SSRI administration is associated with an increase in anxiety consistent with an acute increase in 5-HT neurotransmission. Exercise is anxiolytic in humans, and wheel running prevents anxiety-like behavioral consequences of uncontrollable stress in rats, but the effects of exercise on acute fluoxetine-induced anxiety-like behaviors are unknown.

OBJECTIVES

The current studies tested the hypothesis that acute administration of the SSRI fluoxetine would produce behaviors in rats resembling those produced by uncontrollable stress and that these behaviors would be blocked by prior wheel running.

RESULTS

Adult, male Fisher 344 rats administered moderate (10 mg/kg) or high (20 mg/kg) doses of fluoxetine demonstrated exaggerated shock-elicited freezing and an interference with shuttle box escape compared to rats given either saline or low-dose fluoxetine (2.5 mg/kg). Fluoxetine-induced behaviors were similar to, but smaller in magnitude than, those produced by uncontrollable stress and were blocked by pretreatment with the 5-HT(2C) receptor antagonist SB 242084 (1 mg/kg). Rats allowed access to running wheels for 6 weeks were protected against the anxiety-like behaviors produced by a single injection of fluoxetine (10 mg/kg).

CONCLUSIONS

Behavioral effects of acute fluoxetine administration resemble those produced by uncontrollable stress. Results are consistent with the idea that exercise can produce resistance against the anxiogenic effects of acute increases in 5-HT and suggest that acute behavioral effects of antidepressants can depend on history of physical activity.

Transtornos de ansiedade e exercício físico

OBJETIVO: A maioria dos estudos sobre os efeitos ansiolíticos do exercício físico, até meados da década de 90, foram realizados avaliando-se estados de ansiedade, com indivíduos jovens, universitários ou atletas, que podem ser considerados pré-condicionados, limitando a validade das conclusões para populações com ansiedade patológica. Na atualidade, o número de estudos envolvendo pacientes com transtorno de ansiedade aumentou. O presente estudo tem por objetivo a revisão de artigos que discutem a influência do exercício físico nos transtornos de ansiedade. MÉTODO: Foi realizada uma pesquisa no Medline, no período de 1966-1995 e 1996-2006, utilizando-se os descritores: anxiety, panic, phobic disorders, exercise, physical fitness, além de referências cruzadas dos artigos selecionados e análise adicional de referências na literatura específica do tema. RESULTADOS: Os achados demonstraram desenhos heterogêneos assim como limitações metodológicas. As publicações mais recentes são promissoras e acenam para a utilização de exercícios físicos aeróbios como auxiliares das terapêuticas tradicionais no tratamento dos transtornos de ansiedade. CONCLUSÃO: Verificou-se que os exercícios aeróbios cuja intensidade não ultrapasse o limiar de lactato podem ser os mais apropriados, mas ainda não esclarecem as implicações dos exercícios anaeróbios, sugerindo cautela na prescrição de exercícios para indivíduos com ansiedade patológica, principalmente em relação aos exercícios anaeróbios.

Polymorphism in the serotonin transporter gene and moderators of prolactin response to meta-chlorophenylpiperazine in African-American cocaine abusers and controls

Serotonin (5-HT) function is altered in several psychiatric disorders, including cocaine dependence (CD), and its role in impulsive-aggressive behaviors has been widely studied. However, the relationship between psychopathological and behavioral dimensions and mechanisms of 5-HT alterations remains unclear. We investigated the relationship of a polymorphism in the 5' promoter region of the serotonin transporter gene (5-HTTLPR) with prolactin (PRL) response to meta-chlorophenylpiperazine (m-CPP) in a sample of 68 African-American individuals, 35 CD subjects and 33 controls. We also examined whether measures of impulsivity, hostility and sensation seeking influenced the relationship between the 5-HTTLPR polymorphism and PRL response to m-CPP in this sample. Individuals with the SS genotype showed significantly heightened PRL response to the challenge compared with the LL and LS genotypes. No influence of gender or substance abuse condition was observed. Hostility was associated with blunted PRL response in the total sample. Cocaine abuse was the most significant moderator of DeltaPRL (peak PRL-baseline PRL), and the interaction of genetic, behavioral and psychopathological measures helped predict most of the observed DeltaPRL (62.5%). Although these results need replication, variation in the 5-HTTLPR gene appears to influence measures of 5-HT function and interact with disease state and personality dimensions to account for 5-HT disturbances in African-American populations.

Relationship of disinhibition and aggression to blunted prolactin response to meta-chlorophenylpiperazine in cocaine-dependent patients

RATIONALE

Considerable evidence indicates that serotonergic (5-HT) mechanisms may mediate central effects of cocaine, and disinhibition and aggression.

OBJECTIVE

We investigated whether prolactin (PRL) response to meta-chlorophenylpiperazine (m-CPP), a mixed 5-HT agonist/antagonist, differed between abstinent cocaine-dependent patients and controls and whether m-CPP challenge responses were related to measures of disinhibition and aggression.

METHODS

Thirty-five cocaine-dependent African-American subjects who were abstinent for at least 2 weeks and 33 African-American controls underwent assessments of disinhibition and aggression and a challenge with 0.5 mg/kg of oral m-CPP.

RESULTS

The PRL response to m-CPP was compared between cocaine patients and controls and between subgroups categorized high or low based on disinhibition and aggression measures. Hierarchical regressions were used to determine whether behavioral measures predicted deltaPRL (peak PRL-baseline PRL). The PRL response to m-CPP was significantly diminished in cocaine patients compared to controls. The blunting was more robust in cocaine patients with high disinhibition and aggression. Among cocaine patients, the high-disinhibition subgroup showed greater blunting than the low-disinhibition subgroup and there was a trend for the high-aggression subgroup to be more blunted than the low-aggression subgroup. The subgroups of controls did not differ from each other. A combination of disinhibition and aggression measures significantly predicted deltaPRL in cocaine patients.

CONCLUSION

The results indicate that cocaine-dependent patients show disturbances in postsynaptic 5-HT function during early abstinence. It appears that the 5-HT disturbances are more pronounced in the subgroup of cocaine patients with high disinhibition and aggression.

The contribution of anxiety and food restriction on physical activity levels in acute anorexia nervosa

OBJECTIVE

Excessive exercise is present in 40%-80% of anorexia nervosa (AN) patients. Hyperactivity often plays a role in developing and maintaining AN and represents an obstacle to weight gain in refeeding. Interconnections among caloric restriction, psychopathology, and physical activity in humans with AN are poorly investigated.

METHODS

Physical activity and food restriction during the last 3 months and status of body image/slimness ideal were assessed by the Structured Interview of Anorexia and Bulimia Nervosa (SIAB) in 30 adolescent patients with acute AN at admission to inpatient treatment. Anxiety, depression, and obsessive-compulsiveness were assessed with the Symptom Check-List-90-Revised (SCL-90-R). A regression model based on the independent variables body mass index, food reduction, body image/slimness ideal, anxiety, depression, and obsessive-compulsiveness was calculated to determine the relevant prediction variables of physical activity.

RESULTS

The regression model explained 64% (R(2) = .64, p = .000) of the variance of physical activity. Only food restriction (p = .006) and anxiety (p = .004) contributed significantly to the variance.

DISCUSSION

Our results indicate that anxiety symptoms and food restriction synergistically contribute to increased levels of physical activity in the acute phase of AN.

The application of the principles of clinical drug development to pharmacological challenge tests of the serotonergic system

Pharmacological challenge tests of the serotonergic system have extensively been used during the past 20 years and new tests are in development. It is of crucial importance to standardize challenge tests to ascertain that observed variability is due to the state of the challenged system and not caused by variability of the test itself. This is even more important now that challenge tests increasingly are used in complex studies (e.g. in combination with neuroimaging and in large population studies with repeated tests over time). The Guideline for Good Clinical Practice may be of great help in the standardization of these tests. This is a recently developed guideline for pharmaceutical drug-development, which increasingly is used as a reference for all research in humans. To exemplify the possible usefulness of this approach, we apply it to meta-chlorophenylpiperazine, one of the most commonly used drugs in serotonergic challenge tests. We conclude that much can be learned from the development of this particular challenge. In the discussion, we address general issues that emerged from this review and their relevance to the development of future challenge tests.

Discriminative stimulus effects of m-chlorophenylpiperazine as a model of the role of serotonin receptors in anxiety

Serotonin is known to play a role in anxiety. The roles of serotonin reuptake and 5-HT1A receptors have been well characterized, but the contribution of other serotonin receptor subtypes is not as clear. 1-(3-Chlorophenyl)-piperazine (mCPP), which binds non-selectively to a wide range of serotonin receptors, has often been used to produce anxiety in humans and in animal models. Because functional assays indicate that mCPP is significantly more potent at 5-HT2C receptors, it may serve as a tool to investigate the contribution of 5-HT2C receptors to anxiety. This paper reviews the results of behavioral tests using mCPP, including the drug discrimination assay, to model anxiety. Although the discriminative stimulus effects of mCPP do not seem to be a useful screen for general anxiolytics, they do seem to be useful for characterization of the contribution of 5-HT1B and 5-HT2C receptors to the mediation of anxiety-like behaviors.

5-HT1A responsivity in patients with panic disorder before and after treatment with aerobic exercise, clomipramine or placebo

Blunted neuroendocrine and physiological responses to the selective 5-HT(1A) receptor agonist, ipsapirone, have been observed in patients with panic disorder and/or agoraphobia (PDA). In order to examine whether this hyporesponsiveness to ipsapirone is modified by pharmacological or non-pharmacological therapeutic interventions, challenges with an oral dose of ipsapirone (0.3 mg/kg) and placebo were performed in patients with PDA before and after 10 weeks of treatment with clomipramine, aerobic exercise and placebo. Before treatment, administration of ipsapirone was followed by significant increases of cortisol, anxiety and other psychopathological symptoms in comparison to the placebo challenge. In addition, a significant decrease of body temperature was observed. After the 10-week treatment period, the psychological responses to ipsapirone were significantly reduced in the clomipramine and the exercise group. In contrast, there was a non-significant trend towards higher cortisol responses after clomipramine and exercise treatment. The hypothermic response to ipsapirone was significantly reduced by clomipramine treatment. In conclusion, our results demonstrate that effective treatment of panic disorder has divergent effects on the psychological, neuroendocrine and temperature responses to ipsapirone.

Altered states: the clinical effects of Ecstasy

Ecstasy is the second most widely abused illegal drug in Europe. Ecstasy is the colloquial name for 3,4-methylenedioxymethamphetamine (MDMA), but not all Ecstasy tablets contain MDMA. When taken in hot, crowded environments, Ecstasy/MDMA users have developed acute complications that have had fatal consequences. Epidemiological evidence indicates that adverse reactions to Ecstasy/MDMA intoxication are rare and idiosyncratic. Potential mechanisms of action are reviewed. In animal studies, MDMA damages serotonergic fibres and reduces the number of serotonin transporter sites within the CNS. Demonstration of neurotoxicity in human users of Ecstasy is hampered by a number of confounds that the majority of published studies have failed to address. These confounds are reviewed and their impact is discussed.