The complex relationship between seizures and behavior: an illustrative case report

Epilepsy and behavior have a complex, often intriguing relationship. We report here the interesting case of Mrs. A, who presented with depression and developed seizures and an ictal psychosis precipitated by use of a selective serotonin reuptake inhibitor. She subsequently presented with forced normalization characterized by affective somatoform and hysterical manifestations.

Tobacco chippers show robust increases in smoking urge after alcohol consumption

OBJECTIVE AND RATIONALE

Heavy social drinkers often engage in occasional cigarette smoking, especially in the context of consuming large quantities of alcohol. The current study assessed alcohol's effects on smoking urge as a function of alcohol dose and time course in tobacco chippers with heavy social drinking patterns.

METHOD

The study assessed 39 chippers who underwent three separate evening sessions. Each subject received a placebo (1% volume alcohol as a taste mask), a low alcohol dose (two to three drinks equivalent), and a high alcohol dose (four to five drinks equivalent) in random order. No smoking was permitted during the sessions and the participants were abstinent from smoking for at least 3 h before arrival. Throughout the session, cigarette craving was assessed by the Brief Questionnaire of Smoking Urges and alcohol response was assessed by the Biphasic Alcohol Effects Scale (BAES).

RESULTS

The results showed that alcohol significantly increased cigarette craving in a dose-dependent manner (p<0.001). At the high alcohol dose, craving was heightened during the rising portion of the blood alcohol curve (BAC). There was a strong relationship between BAC and craving for positive reinforcement and this relationship was partially mediated by BAES stimulation, but not sedation.

CONCLUSIONS

The findings show that alcohol directly increases smoking urge in chipper smokers. Tobacco chippers may crave cigarettes more during heavier than during lighter drinking bouts, and this effect appears to be driven by heightened stimulation levels rather than as a means to offset alcohol's sedative effects.

Clinical experience with risperidone in the treatment of behavioral and psychological symptoms of dementia

Dementia is a neuropsychiatric disorder characterized by cognitive impairment and behavioral and psychological symptoms. The efficacy and tolerability of risperidone for treating dementia-associated psychological and behavioral disturbances were evaluated in a study of 135 patients aged 60-85 years with DSM-IV diagnoses of Alzheimer's disease. All were treated with risperidone at a starting dose of 0.5 mg once daily at bedtime. After the first 3 days of therapy the dosage was increased to 1 mg in 2 doses (morning and evening), then a further 0.5 mg was added (alternatively in the morning and in the evening) every three days until attenuation of the psychiatric symptoms. The response to treatment was evaluated for a period of 12 weeks by the Neuropsychiatric Inventory (NPI) and the Behavioral Pathology in Alzheimer's Disease Rating Scale (BEHAVE-AD). Both NPI and BEHAVE-AD were administered at the baseline visit, and after 4 and 12 weeks of therapy. Tolerability was assessed by the incidence of clinically evident side effects. The mean dose at endpoint was 1 mg/day of risperidone. The mean NPI score was 28.80+/-13.92 at start, 15.55+/-11.25 after 4 weeks and 8.30+/-7.00 at endpoint. The reduction in mean scores at 4 and 12 weeks was statistically significant in most of the Neuropsychiatric Inventory items, except for appetite disorders (p<0.0001). The mean BEHAVE-AD score was 20.44+/-3.92 at start, 13.50+/-11.39 after 4 weeks and 8.03+/-7.80 at endpoint. All the items showed a statistically significant improvement after 4 and 12 weeks (p<0.0001). The results were better at 12 than at 4 weeks. In our elderly patients with dementia low-dose risperidone was well tolerated and associated with reductions in BPSD, in particular agitation, aggression, irritability, delusions, sleep disorders, anxiety and phobias.

Multidrug-resistance gene 1-type p-glycoprotein (MDR1 p-gp) inhibition by tariquidar impacts on neuroendocrine and behavioral processing of stress

The multidrug-resistance gene 1-type p-glycoprotein (MDR1 p-gp) is a major gate-keeper at the blood-brain barrier (BBB), protecting the central nervous system from accumulation of toxic xenobiotics and drugs. In addition, MDR1 p-gp has been found to control the intracerebral access of glucocorticoid hormones and thus to modulate the activity of the hypothalamic-pituitary-adrenocortical (HPA) system. In view of the implication of glucocorticoids in the control of behavior, we examined how acute pharmacological inhibition of MDR1 p-gp at the BBB by tariquidar (XR9576; 12 mg/kg, PO) impacts the neuroendocrine and behavioral processing of stress in C57BL/6JIcoHim inbred mice. Inhibition of MDR1 p-gp at the BBB did not alter emotional behavior at baseline. However, mice that were sensitized by water-avoidance stress, a mild psychological stressor, displayed significantly reduced anxiety-related behavior in the elevated plus-maze test when treated with tariquidar. Tariquidar, however, had no effect on stress-coping performance assessed in the forced swim test. Investigating the impact of acute MDR1 p-gp inhibition on the glucocorticoid system, we observed a significant attenuation of the mild stress-induced increase of plasma corticosterone after tariquidar administration. In order to examine whether the anti-anxiety effect of tariquidar in sensitized animals is mediated by glucocorticoids, the animals were treated with corticosterone (1mg/kg, SC) immediately after exposure to water-avoidance stress. Corticosterone caused a significant anxiolytic-like effect in this stress-related anxiety protocol, whereas tariquidar could not further enhance corticosterone's anti-anxiety effects. The current data show for the first time that pharmacological inhibition of MDR1 p-gp at the murine BBB by tariquidar alters emotional behavior and HPA axis activity. By facilitating the entry of corticosterone into the brain, tariquidar enhances feedback inhibition of the HPA system and in this way improves anxiety-related stress processing. These findings highlight a novel approach to the treatment of stress-related affective disorders in humans.

Are there sex differences associated with the effects of ecstasy/3,4-methylenedioxymethamphetamine (MDMA)?

Sex has been identified as an important factor in moderating the effects of several drugs of abuse. Given the increasing popularity of ecstasy (3,4-methylenedioxymethamphetamine [MDMA]) use, it is important for researchers and clinicians to understand the factors that may influence its pharmacological actions to improve education, harm reduction and treatment efforts. This review focuses on preclinical and clinical research that examines the role of sex as an independent variable in the effects of ecstasy/MDMA. A systematic search of PsycINFO and MEDLINE electronic databases from 1966 to April 2006 was conducted. Both preclinical and clinical studies show a sexually dimorphic pattern in the acute, subacute and possibly long-term effects of ecstasy/MDMA. Specifically, adult females are more sensitive than males to the acute and subacute physical and psychological effects of ecstasy/MDMA and long-term alterations in aspects of 5-HT functioning. Conversely, males are more sensitive to the acute physiological effects of ecstasy/MDMA. These findings are consistent with research outcomes reported for other substances such as amphetamines and cocaine. Potential reasons for these sex differences and directions for future research are discussed.

The effects of fluoxetine on the subjective and physiological effects of 3,4-methylenedioxymethamphetamine (MDMA) in humans

OBJECTIVE

The purpose of this study was to investigate the role of serotonin (5-HT) in the effects of oral 3,4-methylenedioxymethamphetamine (MDMA) in humans.

MATERIALS AND METHODS

The subjective and physiological effects of 1.5 mg/kg MDMA were evaluated after 20 mg fluoxetine in eight recreational MDMA users in a double-blind, placebo-controlled study. During phase 1, participants were maintained on placebo for at least 5 days and tested with MDMA and placebo on separate sessions. In phase 2, the procedure was the same except fluoxetine was administered daily for at least 5 days. During sessions, placebo or fluoxetine was given 1 h before the session drug and effects were measured over the next 7 h.

RESULTS

MDMA increased positive-like subjective effects on all the Addiction Research Center Inventory scales; Arousal, Elation, Positive Mood, and Vigor on the Profile of Mood States; Drug Liking, Friendly, Good Drug Effect, High, Stimulated, and Talkative on the Visual Analog Scale; and End-of-Session Liking and Crossover Point on the Multiple Choice Procedure. MDMA also increased measures of anxiety. On the Hallucinogenic Rating Scale, all scales except Volition were increased. MDMA also increased blood pressure and heart rate. Fluoxetine treatment attenuated most of the positive-like subjective effects including the Affect and Soma scales of the Hallucinogen Rating Scale. In addition, heart rate but not blood pressure increases were reduced.

CONCLUSIONS

These results suggest that blockade of 5-HT reuptake by fluoxetine can dampen the effects of MDMA and further supports the role of 5-HT in its behavioral effects in humans.

The impact of cannabis on driving

BACKGROUND

Cannabis is known to have detrimental effects on human performance and may also affect driving adversely. However, studies designed to examine this issue have provided equivocal findings. We set up this study to further determine the effect of cannabis on driving.

METHODS

We used a cross-sectional, case-control design with drivers aged 20-49 who were involved in a fatal crash in the United States from 1993 to 2003; drivers were included if they had been tested for the presence of cannabis and had a confirmed blood alcohol concentration of zero. Cases were drivers who had at least one potentially unsafe driving action recorded in relation to the crash (e.g., speeding); controls were drivers who had no such driving action recorded. We calculated the crude and adjusted odds ratios (ORs) of any potentially unsafe driving action in drivers who tested positive for cannabis but negative for alcohol consumption. In computing for the adjusted OR, we controlled for age, sex, and prior driving record.

RESULTS

Five percent of drivers tested positive for cannabis. The crude OR of a potentially unsafe action was 1.39 (99% CI = 1.21-1.59) for drivers who tested positive for cannabis. Even after controlling for age, sex, and prior driving record, the presence of cannabis remained associated with a higher risk of a potentially unsafe driving action (1.29, 99% CI = 1.11-1.50).

CONCLUSION

Cannabis had a negative effect on driving, as would be predicted from human performance studies. This finding supports the need for interventions to decrease the prevalence of driving under the influence of cannabis, and indicates that further studies should be conducted to investigate the dose-response relationship between cannabis and safe driving.

The concepts of remission and recovery in schizophrenia

OBJECTIVE

To examine the past and current research into the concepts of remission and recovery in schizophrenia.

DATA SOURCES

An electronic literature search of studies published between January 1990-April 2005 examining the concepts of remission and recovery in schizophrenia and the treatment of schizophrenia with antipsychotic agents was performed using Medline and EMBASE. Primary research parameters were 'schizophrenia', 'remission', 'recovery', 'meta-analysis', 'antipsychotics', 'atypicals', 'conventional', 'cognition', 'function' and 'quality of life'.

STUDY SELECTION

English language articles, original research articles, reviews and other articles of interest were reviewed.

DATA EXTRACTION

Data quality was determined by publication in the peer-reviewed literature and the most important information was identified.

DATA SYNTHESIS

A number of different definitions of remission and recovery have been previously used, which has made comparison of study results problematic. Recently, the first operational definition of remission, based on Diagnostic and Statistical Manual of Mental Disorders, fourth edition criteria (DSM-IV) for schizophrenia, was developed. It is hoped that this will provide a standard tool for assessing the effectiveness of treatments for schizophrenia. Recovery, which encompasses both symptom remission and more functional aspects of patient's well being, such as cognition, social functionality and quality of life, is still to be satisfactorily defined. Although recent studies on new generation antipsychotics have examined some proxy outcomes related to recovery, further research is required.

CONCLUSIONS

Until the definition for 'recovery' is further elucidated, factors such as symptom control and remission, and functional aspects of recovery such as improvements in cognition and social functioning, which are quantifiable, should be used as measures of treatment outcome and markers of recovery.

Neurobehavioral performance of adult and adolescent agricultural workers

There are many occupational hazards associated with working in agriculture including risk of injury and exposure to pesticides. Research examining neurobehavioral effects of pesticide exposure have focused primarily on the acute effects in adults working in agriculture. Organophosphate poisoned populations have shown a consistent pattern of deficits when compared to a non-exposed or non-poisoned population on measures of motor speed and coordination, sustained attention, and information processing speed. Fewer studies have examined the effect of long-term low-level exposure on nervous system functioning in agricultural workers. Pesticides are thought to pose a considerably higher risk to children than to adults, yet little is known about the extent or magnitude of health problems related to occupational exposure to pesticides in children and adolescents. The present study compared the neurobehavioral performance of adolescents and adults working in agriculture and examined the impact of years working in agriculture on neurobehavioral performance. One hundred seventy-five Hispanic adolescent and adults completed a neurobehavioral test battery consisting of 10 computer-based tests measuring attention, response speed, coordination and memory. Age, gender, school experience, and years working in agriculture all impacted performance on the neurobehavioral tests. Comparison of adult and adolescents did not reveal decreased neurobehavioral performance in adolescents. On several tests the adolescents performed better than adult counterparts. The adolescents and adults were engaged in comparable agricultural working environments at the time of the neurobehavioral testing. These findings suggest that, at the time of exposure to pesticides, adolescents are not more vulnerable to the effects of working in agriculture. Evidence from this study suggests that cumulative exposure to low levels of pesticides over many years of agricultural work is associated with neurological impairment as measured by the Selective Attention, Symbol-Digit, Reaction Time tests. Experience handling pesticides was also associated with deficits in neurobehavioral performance.

The Psychopharmacology of European Herbs with Cognition-Enhancing Properties

Extensive research suggests that a number of plant-derived chemicals and traditional Oriental herbal remedies possess cognition-enhancing properties. Widely used current treatments for dementia include extracts of Ginkgo biloba and several alkaloidal, and therefore toxic, plant-derived cholinergic agents. Several non-toxic, European herbal species have pan-cultural traditions as treatments for cognitive deficits, including those associated with ageing. To date they have not received research interest commensurate with their potential utility. Particularly promising candidate species include sage (Salvia lavandulaefolia/officinalis), Lemon balm (Melissa officinalis) and rosemary (Rosmarinus officinalis). In the case of sage, extracts possess anti-oxidant, estrogenic, and anti-inflammatory properties, and specifically inhibit butyryl- and acetyl-cholinesterase. Acute administration has also been found to reliably improve mnemonic performance in healthy young and elderly cohorts, whilst a chronic regime has been shown to attenuate cognitive declines in sufferers from Alzheimer's disease. In the case of Melissa officinalis, extracts have, most notably, been shown to bind directly to both nicotinic and muscarinic receptors in human brain tissue. This property has been shown to vary with extraction method and strain. Robust anxiolytic effects have also been demonstrated following acute administration to healthy humans, with mnemonic enhancement restricted to an extract with high cholinergic binding properties. Chronic regimes of aromatherapy and essential oil respectively have also been shown to reduce agitation and attenuate cognitive declines in sufferers from dementia. Given the side effect profile of prescribed cholinesterase inhibitors, and a current lack of a well tolerated nicotinic receptor agonist, these herbal treatments may well provide effective and well-tolerated treatments for dementia, either alone, in combination, or as an adjunct to conventional treatments.

Cerebral metabolic effects of intravenous glycine in healthy human subjects

Enhancing N-methyl-D-aspartate (NMDA) receptor function via increasing synaptic concentrations of glycine is currently investigated as a novel approach to treat schizophrenia. The neural correlates of enhanced NMDA receptor function in humans, however, are unclear to date. The present study determines the effects of intravenous administration of the glycine on regional cerebral metabolic rate of glucose (rCMRGlu) in healthy control subjects by using [18F]fluorodeoxyglucose and positron emission tomography and on neuropsychological behavioral measures. Thirteen healthy volunteers were recruited, and 12 subjects completed the protocol. These individuals participated in 1 magnetic resonance imaging study and 2 [18F]fluorodeoxyglucose positron emission tomography studies. In a double-blind, randomized, controlled, crossover design, participants received on one test day an intravenous glycine infusion and on the other test day a placebo infusion. There were no significant behavioral and neuropsychological effects of glycine compared with placebo. However, there was a significant reduction of whole-brain CMRGlu during administration of glycine compared with placebo (t = 2.60, df = 11, P = 0.023). In the a priori-selected regions of interest, there was a significant reduction in the cerebellum (t = -3.18, df = 11, P = 0.009) and the dorsolateral prefrontal cortex (t = -2.31, df = 11, P = 0.041). When corrected for whole-brain CMRGlu, rCMRGlu differences were not significant. This study suggests that studies of whole-brain cerebral metabolism may be useful for studying glycine-related mechanisms in healthy humans because there is not a clear cognitive or behavioral signal related to glycine administration at doses thought to be important clinically in patient populations.

Relaxing effect of ylang ylang oil on humans after transdermal absorption

The aim of this study was to investigate the effects of ylang ylang oil (Cananga odorata, Annonaceae) on human physiological parameters and self-evaluation after transdermal absorption. Forty healthy volunteers participated in the experiments. Physiological parameters recorded were skin temperature, pulse rate, breathing rate and blood pressure. Self-evaluation was assessed by means of visual analog scales (VAS). The ylang ylang oil caused a significant decrease of blood pressure and a significant increase of skin temperature. At the behavioral level, subjects in the ylang ylang oil group rated themselves more calm and more relaxed than subjects in the control group. These findings are likely to represent a relaxing effect of the ylang ylang oil and provide some evidence for the usage of the ylang ylang oil in aromatherapy such as causing a relief of depression and stress in humans.

Oral progesterone decreases saccadic eye velocity and increases sedation in women

The aim of this study was to investigate the neurophysiological and behavioural effects of a single dose of progesterone in women. Allopregnanolone is a metabolite of progesterone and a potent positive modulator of the GABA(A) receptor and produces sedative and anxiolytic effects. This study was designed to examine the effect of oral progesterone and the metabolite allopregnanolone in women. Women (n=15) in their follicular phase received oral progesterone (400mg) or placebo. Dependent measures included plasma levels of progesterone and allopregnanolone, saccadic eye velocity (SEV), subjective ratings (visual analogue scales), and reaction time. Administration of progesterone decreased SEV and increased sedation. This effect is probably due to enhanced GABA activity.

Methylphenidate modulates cerebral post-stroke reorganization

OBJECTIVE

We hypothesized that a single dose of methylphenidate (MP) would modulate cerebral motor activation and behavior in patients having suffered a subcortical stroke.

METHODS

Eight men with a single stroke on the corticospinal tract resulting in a pure motor hemiparesia were included in a randomized, cross-over, double-blind, placebo-controlled study. Patients were first evaluated 17 days after stroke onset by validated neurological scales, motor tests and fMRI (flexion/extension of the digits) after 20 mg MP or placebo. Seven days later, the patients underwent the same protocol and received the drug they had not taken at the first evaluation. Each patient was his own control.

RESULTS

Placebo intake did not change performance. MP compared to placebo elicited a significant improvement in motor performance of the affected hand at the finger tapping test. MP induced: (1) a hyperactivation of the ipsilesional primary sensorimotor cortex including the motor hand and face areas and of the contralesional premotor cortex; (2) a hypoactivation of the ipsilesional anterior cingulum. Hyperactivation in the face motor area correlated positively with the improvement in performance.

CONCLUSION

We demonstrated that the reorganized network may efficiently be targeted by the drug and that the effect of MP might partly rely on an improvement in attention/effort through cingulum modulation.

A large, naturalistic, community-based study of rivastigmine in mild-to-moderate AD: the EXTEND Study

BACKGROUND

Previous studies in Alzheimer's Disease (AD) suggest a benefit from switching from one cholinesterase (ChE) inhibitor to another in the event of treatment failure on the index agent. This observational, open-label study sought to evaluate the efficacy of the ChE inhibitor rivastigmine on cognition, functional autonomy and behavior in patients with mild-to-moderate AD previously treated with other ChE inhibitors (switched patients) as well as in those previously ChE-inhibitor-naive (de novo users).

METHODS

Patients were eligible for a switch if they experienced a lack or loss of efficacy or had experienced intolerance to prior ChE inhibitor therapy. Rivastigmine was initiated at a dose of 1.5 mg b.i.d. and titration was done as per standard medical practice. Efficacy was assessed using the mini-mental state examination (MMSE) and an abbreviated version of the Clinician's Global Impression of Change (CGI-C) at Month 3 and Month 6. Caregiver burden was also assessed at Month 6 using a self-rated scale.

RESULTS

Overall, 2633 subjects were enrolled in this study. The mean MMSE improved from 20.6 at baseline to 21.5 at Month 6. More patients improved than deteriorated on every domain of the CGI-C. Caregivers felt less burdened after the 6 month evaluation period. Efficacy parameters demonstrated favorable results for both de novo and switched patients, but more so in the first group.

LIMITATIONS

Open-label studies have an inherent potential for bias by both the caregiver and the physician. In this study, there was also a large percentage of missing patient records for each of the follow-up visits (Months 3 and 6).

CONCLUSIONS

Patients with mild-to-moderate AD switched from previous ChE inhibitor therapy to rivastigmine can obtain measurable benefits, although the treatment effect may be less than in de novo patients. Further research into switching cholinesterase inhibitors is warranted.

Behavioral sensitization, alternative splicing, and d3 dopamine receptor-mediated inhibitory function

Behavioral sensitization, the progressive and enduring augmentation of certain behaviors following repetitive drug use, alters rodent locomotion in a long-standing manner. The same dopamine pathways playing an important role in drug dependence and psychosis also play a critical role in sensitization. Individual dopamine receptor subtypes have markedly different functional responses to stimulation, with D3 dopamine receptor stimulation inhibiting rodent locomotion. The D3 receptor has highest affinity of the dopamine receptor subtypes for dopamine, and is occupied to a greater degree following stimulant drug administration. D3 receptor activity may be regulated through the expression of an alternatively spliced, truncated receptor isoform (termed 'D3nf') altering receptor localization and function via dimerization with the full-length subunit. The expected physiological response to repetitive drug administration is tolerance. Tolerance of D3 receptor inhibition of locomotion would contribute to sensitization to stimulant drugs. We hypothesize that repetitive D3 receptor stimulation contributes to the development of behavioral sensitization through decreased responsivity of D3-receptor-mediated locomotor inhibition. Increased D3nf expression may direct altered receptor localization and subsequent release of D3-receptor-mediated inhibition, contributing to the expression of sensitization. These hypotheses follow directly from the affinities of the receptor subtypes for dopamine; dopamine concentrations following stimulant administration; the effects of individual dopamine receptor subtype stimulation on locomotion; and the expected homeostatic response of the system to perturbation by drug. Clarifying these mechanisms underlying sensitization may suggest new interventions for neuropsychiatric conditions in which dopamine plays an important role, including psychosis, drug dependence, and Parkinson's disease. This information may also elucidate a previously unrecognized mechanism regulating receptor trafficking and desensitization.

Differential effects of naltrexone on cardiac, subjective and behavioural reactions to acute ethanol intoxication

OBJECTIVE

Alcohol may have psychomotor stimulant properties during the rising limb of the blood alcohol curve at commonly self-administered doses. Increased heart rate (HR) immediately after alcohol consumption may serve as an indicator or marker of such properties, which appear to be potentially opiate-mediated and dopamine-dependent. Naltrexone, an opiate antagonist, has been used successfully in the treatment of alcoholism and may produce its therapeutic effects through its effects on alcohol metabolism or by blocking alcohol's rewarding effects. We hypothesized that, if naltrexone blocks the psychomotor stimulant properties of ethanol, then it would decrease or eliminate the HR increase associated with acute alcohol intoxication and that this would be independent of any effect on alcohol metabolism.

METHODS

Twenty male subjects were administered placebo and alcohol (1.0 mL 95% USP ethanol/kg body weight) in a laboratory setting on one day and naltrexone (50 mg) and alcohol on another (counterbalanced). We assessed all subjects for a change in HR and for a subjective and behavioural response from 35 to 170 minutes after drug or alcohol administration.

RESULTS

The placebo and alcohol mix produced a significant mean HR increase from baseline (F(1,95) = 46.01, p < 0.0001, Cohen's d = 0.62), while naltrexone and alcohol did not (nonsignificant). The significant effects of naltrexone on blood alcohol level did not account for the effect of naltrexone on alcohol-induced HR change but did account for alterations in subjective and behavioural response to alcohol.

CONCLUSIONS

Naltrexone appears to substantially reduce the HR increase that is characteristic of alcohol intoxication. This finding appears to lend moderate support to the notions that, first, naltrexone has differential effects on alcohol reactions and, second, that it specifically blocks the acute psychomotor stimulant properties of alcohol.

A developmental comparison of the neurobehavioral effects of ecstasy (MDMA)

The entactogen +/-3,4-methylenedioxymethamphetamine (MDMA or ecstasy) is a popular recreational drug among college, high school, and, occasionally, middle school students. Preclinical research examining the acute and long-term effects of MDMA has predominately been conducted in reproductively mature subjects but there has been increasing interest in adolescent and in utero exposure. This review examines the acute and long-term responses to MDMA during perinatal, adolescent, and adult periods. The ability of MDMA to alter core body temperature emerges gradually during ontogeny while a reduction in body weight is evident at all ages. Learning and working-memory are also altered independent of the developmental stage of exposure. Current evidence suggests adults are more sensitive to the long-term serotonin depletions following MDMA but younger ages also exhibit substantial and rapid neuroplasticity. Sexually dimorphic MDMA responses have been identified for the acute hyperthermic and motoric effects of MDMA with pubescent males being especially susceptible. Several physiological, behavioral, and neurochemical MDMA issues requiring further study are also outlined.

[The neuropsychology of epilepsy: what factors are involved?]

INTRODUCTION

The epileptic child is three times more likely to have cognitive problems from other neurological pathologies, depending on three facts: the effect exerted by the epilepsy itself, any associated previously-existing neuropsychosocial deficits, and the side effects of the antiepileptic drug (AED). A certain degree of deterioration is universally accepted, although the factors involved in its production are not specified, but are generally accepted as being due to multiple causes. We analyse the relation between neuropsychology and epilepsy in neuropaediatrics.

DEVELOPMENT

The relation between epilepsy and behaviour must be seen as the exception rather than the rule, unless there are co-existing personality disorders and/or mental deficiency. The cognitive effects of AED depend on the drug, on the dosages employed and the polypharmacy, and these effects can be both adverse and favourable. The differences observed between one drug and another are open to criticism, although monitored administration of suitable doses generally produces moderate adverse side effects, as evaluated using reliable appraisal methods (MIDDRA). Scaling time in the introduction of the drug is important, especially with some new AED. The mechanisms governing production vary, but an understanding of the mechanism of action improves cognitive functioning thanks to the control over the seizures. In infancy, idiopathic cognitive reactions are produced. The main disorders are a diminished reaction and information processing time with alterations affecting memory, attention and language.

CONCLUSIONS

Epilepsy is associated to a number of different, generally moderate, cognitive problems. The age of onset, the type of syndrome, its aetiology, the response to treatment and polypharmacy are multifactorial elements conditioning the side effects. There is a need for batteries of tests capable of forecasting the future and controlling the progression of cognition during treatment. The side effects of AED affecting cognition and behaviour are generally moderate, but they may be important in the case of a particular child.

Treatment of behavioural, cognitive and circadian rest-activity cycle disturbances in Alzheimer's disease: haloperidol vs. quetiapine

This 5-wk, open-label, comparative study investigated the effects of quetiapine and haloperidol on behavioural, cognitive and circadian rest-activity cycle disturbances in patients with Alzheimer's disease (AD). Out of a total of 30 patients enrolled in the study, there were 22 completers, 11 in the quetiapine group (mean age 81.9+/-1.8 yr, mean baseline MMSE 19.9+/-1.3, mean dose 125 mg) and 11 in the haloperidol group (mean age 82.3+/-2.5 yr, mean baseline MMSE 18.1+/-1.3, mean dose 1.9 mg). As shown in the Neuropsychiatric Inventory, both medications reduced delusion and agitation, whereas quetiapine additionally improved depression and anxiety. Haloperidol worsened aberrant motor behaviour and caused extrapyramidal symptoms. In the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) neuropsychological test battery which assessed cognitive parameters, quetiapine improved word recall; significant interaction terms revealed differences between quetiapine and haloperidol in word-list memory and constructional praxis. According to the Nurses' Observation Scale for Geriatric Patients (NOSGER) quetiapine improved instrumental activities of daily living. Actimetry documented the circadian rest-activity cycle before and after treatment. Sleep analysis revealed that patients receiving quetiapine had shorter wake bouts during the night, whereas patients receiving haloperidol had fewer though longer immobile phases. The study provides evidence that quetiapine at a moderate dose may be efficacious in treating behavioural disturbances in AD, with better tolerability than haloperidol.

Alcohol, Neurotransmitter Systems, and Behavior

Alcohol affects several neurotransmitter systems within the brain. In this article, the author describes its effects on 5 major ones: glutamate, gamma-amino-butyric acid (GABA), dopamine, serotonin, and opioid systems. The author also notes the interactions and interdependencies of these transmitters, and provides details on both immediate effects and long-term adaptations. Last, the author explains several psychopharmacological treatments for alcoholism and the effects of these treatments on transmitters, and draws conclusions.

Neurotensin: role in psychiatric and neurological diseases

Neurotensin (NT), an endogenous brain-gut peptide, has a close anatomical and functional relationship with the mesocorticolimbic and neostriatal dopamine system. Dysregulation of NT neurotransmission in this system has been hypothesized to be involved in the pathogenesis of schizophrenia. Additionally, NT containing circuits have been demonstrated to mediate some of the mechanisms of action of antipsychotic drugs, as well as the rewarding and/or sensitizing properties of drugs of abuse. NT receptors have been suggested to be novel targets for the treatment of psychoses or drug addiction.

Effects of oestrogen on cognition: what have we learned from basic research?

The results of clinical and basic research conducted over the past two decades have implicated a role for oestrogen in modulating cognitive function. This review focuses on what the results of research using female rodent models have revealed about the effects of oestrogen on mammalian cognition. Increased levels of oestrogen are associated with increased dendritic spine and synapse density in the hippocampus, a brain area important for learning and memory. However, the role of oestrogen in the modulation of performance on tasks of learning and memory is complex because it exerts enhancing effects on some tasks and impairing effects on others. Hypotheses have been offered to explain these varied actions, including differentiating the effects of oestrogen on cognitive processes required to complete tasks and analysing the influence of fluctuating levels of oestrogen on the strategies selected by animals to solve tasks. It is proposed that, when these hypotheses are viewed together and within the context of oestrogen action in the hippocampus and potentially other brain areas, a framework for understanding the varied effects of oestrogen on cognition emerges. The hippocampal-dependent memory system supports the flexible expression of memories and the hippocampal-independent memory system supports development of individual representations. Because of the effects exerted by oestrogen on the structure and function of the hippocampus, it would be expected to enhance performance across a variety of tasks that require hippocampal-dependent flexible expression of memories and would not enhance performance on tasks that involve hippocampal-independent individual representations. This review offers a theoretical model by which the divergent results of studies assessing the role of oestrogen on cognition can be reconciled and suggests that effects of oestrogen on cognition are best understood within the framework of oestrogen action in the brain and the role of those brain areas affected by oestrogen in the mediation of learning and memory.

Treatment of borderline personality disorder with olanzapine

Borderline personality disorder is one of the most problematic psychiatric disorders with aggressiveness and impulsivity as its two main characteristics. Our objective was to determine the efficacy of olanzapine on 20 patients with borderline personality disorder. Results were found to be affirmative in this respect.

A mathematical theory for temporal changes in tolerance to the behavioral effects of alcohol

Temporal changes in the tolerance to alcohol are rarely discussed. In the behavioral theory proposed here, the rate of increase in tolerance during alcohol exposure is described by linear equations with zero intercept. These equations describe the rate of tolerance growth for acute tolerance, the rate of tolerance growth after alcohol dosing (chronic tolerance), and, for cases in which tolerance has been conditioned, the equations also describe changes in the rate of growth of tolerance when the stimulus set changes. This theory does not explain tolerance acquisition, but may be useful in investigating the physiological basis for tolerance acquisition because it provides numerical values for momentary tolerance that can be compared with concurrent physiological changes. The theory is testable and most of the published behavioral data on non-conditioned tolerance are consistent with the proposed theory. New empirical data on conditioned tolerance are needed to evaluate the proposed theory, and the design for an evaluation is suggested here. Despite its limitations, the theory serves as one example of what a mathematical theory for tolerance might be and may stimulate the development of competing theories with which it could be compared empirically.

Why are women from Venus and men from Mars when they abuse cocaine?

Both preclinical and clinical studies have shown sexually dimorphic patterns in behavioral responses to cocaine in all phases of the cocaine addiction process (induction, maintenance, and relapse). Thus, a clear picture is emerging which suggests that the biological basis of sex-specific differences in cocaine addiction resides in the disparate regulation of the CNS by male and female gonadal hormones. This review discusses the role that gonadal hormones play in these sexually dimorphic patterns of behavioral responses to cocaine.

Noradrenaline Might Enhance Assertive Human Social Behaviours: An Investigation in a Flatmate Relationship

OBJECTIVE

The aim of the present study was to explore the role of noradrenaline on the social behaviour of healthy volunteers when they were interacting with a familiar person, their flatmate. Interaction with the flatmate was explored in a cooperative game situation.

METHODS

Ten pairs of same-sex healthy volunteer flatmates aged 18-25 years were recruited for the experiment. All volunteers gave written informed consent and the study was approved by the institutional ethical committee. A randomised, double blind, placebo-controlled crossover trial of reboxetine versus placebo was conducted. In each of the 10 pairs of volunteers, one (subject) volunteered to take the tablets and the other (flatmate) received no treatment. Reboxetine (4 mg/bd) and placebo were administered orally as identical capsules for 2 weeks. The subjects were randomly assigned to receive either reboxetine or placebo first and there was a two-week washout period following the first treatment. At baseline and the end of each treatment, they filled in the Beck Depression Inventory (BDI), Social Adapation Self-Evaluation Scale (SASS), and Aggression Questionnaire (AQ). Then, they were instructed to play the Tangrams game. This task elicits face-valid social behaviours such as cooperation, giving commands and unilateral grasps.

RESULTS

Analysis of covariance showed that there was a statistical trend for reboxetine treatment to increase commands (p=0.055).

CONCLUSION

This study presents preliminary evidence that two weeks' enhancement of noradrenaline transmission induced by reboxetine makes healthy volunteers more self-confident and assertive.

Greater vulnerability to the amnestic effects of ketamine in males

RATIONALE

Gender differences both in response to ketamine in animals and general cognitive functioning in humans have been observed and suggested to be related to modulatory effects of sex hormones on N-methyl-D: -aspartate receptor (NMDA-R) functioning.

OBJECTIVES

The current study aimed to determine whether there were gender differences in response to ketamine in humans.

METHODS

Behavioral data including positive and negative symptoms (Brief Psychiatric Rating Scale), perceptual alterations (Clinician-Administered Dissociative States Scale, CADSS), and "high" and "anxiety" states (Visual Analog Scale) from 295 subjects who participated in a total of 11 placebo-controlled ketamine studies were analyzed. In a subset of subjects, memory (Hopkins Verbal Learning Task: HVLT, n=108) and attention (continuous performance task, n=177) data were also analyzed.

RESULTS

Male participants showed a greater performance decrement on the HVLT after ketamine administration compared to women. Men also reported a greater subjective sense of memory impairment on a CADSS subscale. No other gender differences in behavioral or cognitive measures were observed.

CONCLUSIONS

Men showed a greater vulnerability to the amnestic effects of ketamine than women. Possible explanations of these findings are neuroanatomical and cognitive differences in processing of words in men and women and interactions between sex hormones and NMDA-R function.

Assessing mechanical sensitivity of masseter muscle in lightly anesthetized rats: A model for craniofacial muscle hyperalgesia

In this report, we present a simple and reliable way of assessing mechanical sensitivity of masseter muscle as a model for craniofacial muscle hyperalgesia. Mechanical thresholds that evoke nocifensive hindpaw responses following noxious masseter stimulation were assessed. Masseteric injections of widely used sensitizing agents significantly increased mechanical sensitivity of the muscle in a time dependent manner without affecting other muscles and overlying skin. This lightly anesthetized rodent paradigm allows us to provide calibrated and reliable mechanical stimulus, which is not possible in behaving animals. The technique can be applied to study mechanistic bases for craniofacial muscle tenderness.

Cannabidiol monotherapy for treatment-resistant schizophrenia

Cannabidiol (CBD), one of the major products of the marijuana plant, is devoid of marijuana's typical psychological effects. In contrast, potential antipsychotic efficacy has been suggested based on preclinical and clinical data (Zuardi et al., 2002). In this report, we further investigated the efficacy and safety of CBD monotherapy in three patients with treatment-resistant schizophrenia (TRS). This was an in-patient study. All patients were given placebo for the initial 5 days, and from the 6th to 35th day (inclusive) they received CBD (initial oral dose of 40 mg reaching 1280 mg/day). On the 36th day, CBD treatment was discontinued and replaced by placebo for 5 days, which was subsequently switched to olanzapine for over 15 days. Efficacy, tolerability and side effects were assessed. One patient showed mild improvement, but two patients didn't show any improvement during CBD monotherapy. All patients tolerated CBD very well and no side effects were reported. These preliminary data suggest that CBD monotherapy may not be effective for TRS.

Rituximab (anti-CD20) adjunctive therapy for opsoclonus-myoclonus syndrome

PURPOSE

To determine if rituximab, an anti-CD20 monoclonal antibody, reduces cerebrospinal fluid (CSF) B-cell expansion in opsoclonus-myoclonus syndrome (OMS) and results in clinical improvement.

METHODS

Sixteen children with OMS and increased % CD20 B-cells in CSF received 4 rituximab infusions (375 mg/m IV) as add-on therapy to corticotropin (ACTH), intravenous immunoglobulins, or both, and were reevaluated 6 months later. Outcome measures were clinical (motor function, behavior, sleep) and immunologic (CSF and blood immunophenotype and Ig levels). Controls were 16 age-matched and sex-matched children, who did not have OMS.

RESULTS

After rituximab, 81% of OMS had a lower motor severity score, and 44% improved one severity category. Mean total score decreased by 44% (P = 0.0005). Rituximab reduced rage score, nighttime awakenings, and the number of children with opsoclonus, action myoclonus, drooling, gait ataxia, and rage. Despite a 51% reduction in ACTH dose, 9 of 11 children on ACTH did not relapse. The percentage of CSF CD19 (and CD20) B-cells was lowered in all children (undetectable in 6), with a 90% reduction in the group mean (P = 0.00003). CSF B-cells were no longer expanded compared with controls. In blood, CD19 B-cells decreased (-90%, P = 0.0003), as did the CSF:blood CD19 B-cell ratio (P = 0.00003). Serum IgM fell by 69% (below reference range), with no statistically significant change in IgG or IgA.

CONCLUSIONS

Rituximab seems efficacious and safe as adjunctive therapy for OMS. Selective targeting of CSF B lymphocytes represents a novel and valuable paradigm shift in the therapy for centrally mediated paraneoplastic disorders.

Dopamine-dependent prediction errors underpin reward-seeking behaviour in humans

Theories of instrumental learning are centred on understanding how success and failure are used to improve future decisions. These theories highlight a central role for reward prediction errors in updating the values associated with available actions. In animals, substantial evidence indicates that the neurotransmitter dopamine might have a key function in this type of learning, through its ability to modulate cortico-striatal synaptic efficacy. However, no direct evidence links dopamine, striatal activity and behavioural choice in humans. Here we show that, during instrumental learning, the magnitude of reward prediction error expressed in the striatum is modulated by the administration of drugs enhancing (3,4-dihydroxy-L-phenylalanine; L-DOPA) or reducing (haloperidol) dopaminergic function. Accordingly, subjects treated with L-DOPA have a greater propensity to choose the most rewarding action relative to subjects treated with haloperidol. Furthermore, incorporating the magnitude of the prediction errors into a standard action-value learning algorithm accurately reproduced subjects' behavioural choices under the different drug conditions. We conclude that dopamine-dependent modulation of striatal activity can account for how the human brain uses reward prediction errors to improve future decisions.

Human cognition assessment in drug research

In this article cognition assessments as outcome measures in CNS drug development research are described. An outline is given of the various choices that can be made and the reasons for them, depending on the approach followed. First, a brief historical context is provided of the psychological sciences that have contributed to today's psychopharmacology of cognition assessment. Subsequently, the focus is on identifying cognitive domains and criteria for selecting appropriate tests. In applied cognitive performance assessment in human psychopharmacology, a number of approaches can be recognised, each associated with models that connect cognitive functions with physiological functions and neural structures. The product-oriented approach of cognition assessment is usually characterised by the use of a battery of several cognitive tasks as an assessment instrument and aims to demonstrate an effect of a pharmaceutical substance without much attempt to determine which cognitive process is primarily influenced by a drug. The process-oriented approach precisely defines the cognitive process in terms of at least a single factor linear model of a process (e.g. by manipulating levels of difficulty) and then compares how diseases and drugs modify the parameters of that process. The associated factor analytical-, resource-strategy- and staged information processing models respectively are described. Finally a brief review is presented on possible physiological markers or biomarkers of human cognitive functions.

Intoxicated behavioral disinhibition and the heart rate response to alcohol

This study examined the association between the heart rate (HR) response to alcohol intoxication, which is thought to reflect sensitivity to alcohol-induced reward and alcohol-induced behavioral disinhibition. High- and low-HR responders to alcohol participated in a go/no-go task, under sober and intoxicated conditions. Errors of commission on this task have previously been related to behavioral disinhibition. High-HR responders made more intoxicated commission errors as compared with low-HR responders. High-HR responders also reported increased alcohol consumption, and controlling for the latter did not alter the significant association between high-HR responders and increased intoxicated errors of commission. These results are consistent with previous findings of an increased risk for addictive and disinhibited behavioral propensities in individuals with a high-HR response to alcohol intoxication.

Relationship of prolactin response to meta-chlorophenylpiperazine with severity of drug use in cocaine dependence

RATIONALE

Serotonergic (5-HT) mechanisms appear to mediate central effects of cocaine. Therefore 5-HT disturbances could be associated with drug severity.

OBJECTIVES

We investigated whether prolactin (PRL) response to meta-chlorophenylpiperazine (m-CPP), a mixed 5-HT agonist/antagonist were associated with severity of cocaine use.

METHODS

Thirty-six cocaine-dependent subjects and 33 controls underwent a challenge with 0.5 mg/kg of oral m-CPP. Severity of drug use was assessed using the Addiction Severity Index (ASI).

RESULTS

The PRL response to m-CPP was significantly blunted in cocaine patients compared to controls (F = 21.86, p < 0.001). DeltaPRL (peak PRL-baseline PRL) was negatively correlated with ASI-drug (r = -0.45, p < 0.01), ASI-alcohol (r = -0.32, p < 0.05), and ASI-psychological (r = -0.41, p < 0.01) composite scores, and with the quantity, frequency and duration of drug use (r ranged from - 0.41 to - 0.32, p ranged from < 0.01 to 0.05). Hierarchical regressions showed that ASI-drug composite scores significantly predicted the variance in DeltaPRL after controlling for behavioral and demographic variables (F = 4.27, p < 0.05).

CONCLUSIONS

The results indicate that disturbances in 5-HT function as reflected by a blunted response to m-CPP seem to be primarily associated with severity of drug use and to a lesser, although significant extent with behavioral traits in cocaine-dependent patients.

Neurosteroids, neuroactive steroids, and symptoms of affective disorders

Neurosteroids (NS) are steroids synthesized by the brain. Neuroactive steroids (NAS) refers to steroids that, independent of their origin, are capable of modifying neural activities. NAS bind and modulate different types of membrane receptors. The gamma amino butyric acid (GABA) and sigma receptor complexes have been the most extensively studied. Oxidized ring A reduced pregnanes, tetrahydroprogesterone (THP), and tetrahydrodeoxycorticosterone (THDOC) bind to the progesterone intracellular receptor (PR), and in this way can also regulate gene expression. Animal experimentation showed that salient symptoms of depression, viz., anxiety, sleep disturbances, and memory and sexual dysfunctions, are modulated by NAS. In turn, psychotropic drugs modulate NS and NAS levels. NS levels as well as NAS plasma concentrations change in patients with depression syndromes, the levels return to normal baseline with recovery, but normalization is not necessary for successful therapy. Results from current studies on the evolution of nervous systems, including evolutionary developmental biology as well as anatomical and physiological findings, almost preclude a categorical classification of the psychiatric ailments the human brain succumbs to. The persistence in maintaining such essentialist classifications may help to explain why up to now the search for biological markers in psychiatry has been an unrewarding effort. It is proposed that it would be more fruitful to focus on relationships between NAS and symptoms of psychiatric disorders, rather than with typologically defined disorders.

[Update on gamma-hydroxybutyric acid]

AIMS

The article offers an updated review of the main pharmacological aspects of gamma-hydroxybutyric acid (GHB), as well as its clinical and behavioural effects.

DEVELOPMENT

A number of pharmacological, neurochemical and electrophysiological studies have clearly shown that endogenous GHB plays a role as a neurotransmitter and/or neuromodulator in the central nervous system (CNS). GHB displays specific synthesis, release and reuptake mechanisms, as well as particular binding sites that suggest the existence of a central GHBergic system. This substance, popularly known as 'liquid ecstasy', is also a potentially abusable drug; if administered for prolonged periods of time it can lead to dependence and withdrawal symptoms after the patient stops taking it. Its chief behavioural actions include sedation/sleepiness, induction of absence seizures, catalepsy or reduced aggression, among others. Some of these effects appear to be related to an interaction that has been reported to exist between the GHBergic system and the dopaminergic and GABAergic receptors in the CNS. From the clinical point of view, its use has been approved in some countries to treat the narcoleptic syndrome, and it has also been considered for possible use in the treatment of alcohol or opiate abuse. Finally, recent studies conducted with laboratory animals suggest the existence of a possible neurotoxic effect following prolonged administration in abusable dosages.

CONCLUSIONS

GHB is an extraordinarily interesting compound. It acts as a neurotransmitter/neuromodulator in the CNS. It is also an abusable recreational drug and may also be used to treat a number of different pathological conditions, the most important of which is narcolepsy. The possible development of neurotoxicity following prolonged administration, however, imposes considerable limitations on its usefulness in clinical contexts.

Role of κ- and δ-opioid receptors in the antinociceptive effect of oxytocin in formalin-induced pain response in mice

Oxytocin has been implicated in the modulation of somatosensory transmission such as nociception and pain. The present study investigates the effect of oxytocin on formalin-induced pain response, a model of tonic continuous pain. The animals were injected with 0.1 ml of 1% formalin in the right hindpaw and the left hindpaw was injected with an equal volume of normal saline. The time spent by the animals licking or biting the injected paw during 0-5 min (early phase) and 20-25 min (late phase) was recorded separately. Oxytocin (25, 50, 100 microg/kg, i.p.) dose dependently decreased the licking/biting response, both in the early as well as the late phases. The antinociceptive effect of oxytocin (100 microg/kg, i.p.) was significantly attenuated in both the phases by a higher dose of the non-selective opioid receptor antagonist naloxone (5 mg/kg, i.p.), MR 2266 (0.1 mg/kg, i.p.), a selective kappa-opioid receptor antagonist and naltrindole (0.5 mg/kg, i.p.), a selective delta-opioid receptor antagonist but not by a lower dose of naloxone (1 mg/kg, i.p.) or beta-funaltrexamine (2.5 microg/mouse, i.c.v.), a selective mu-opioid receptor antagonist. Nimodipine, a calcium channel blocker (1 and 5 mg/kg, i.p.) produced a dose-dependent analgesic effect. The antinociceptive effect of oxytocin was significantly enhanced by the lower dose of nimodipine (1 mg/kg, i.p.) in both the phases. Chronic treatment with oxytocin (100 microg/kg/day, i.p. daily for 7 days) did not produce tolerance in both the phases of formalin-induced pain response. The results thus indicate that oxytocin displays an important analgesic response in formalin test; both kappa- and delta-opioid receptors as well as voltage-gated calcium channels seem to be involved in the oxytocin-induced antinociception.

A combined neurophysiological and behavioural study into the stimulating effects of fexofenadine on performance

Antihistamines are known for their sedative effects. However, some studies suggested mild stimulant effects in the case of fexofenadine. The goals of this study are to examine whether fexofenadine possesses stimulating properties and to determine whether such stimulating effects are related to workload. Sixteen healthy volunteers received a single dose of 180 and 360 mg fexofenadine and placebo on separate test days. Drug effects were assessed using a divided attention task (DAT), continuous performance task (CPT) and motor choice reaction time test (MCRT). Sensitivity of the tasks was increased by manipulating the workload during task performance. Event Related brain Potentials (ERPs) were measured in the DAT and CPT to study the underlying neurophysiological processes. An interaction effect of Treatment and Workload was found on tracking performance in the DAT and on movement time in the MCRT. Performance on the DAT was less affected by increments in workload after fexofenadine as compared to placebo. P1 and P3 latency were affected by Treatment x Workload and Treatment respectively and indicated faster attentional and information processing latencies following fexofenadine treatment. Treatment did not influence performance in the CPT task or in the ERPs measured during this task. The MCRT demonstrated faster movement times following fexofenadine treatment. These results suggest that although the neurophysiological data indicate central nervous system (CNS) activation after fexofenadine treatment, the magnitude of the centrally activating effects is too small to produce relevant performance improvement at the behavioural level.

Effect of Saffron (Crocus sativus) on Neurobehavioral and Neurochemical Changes in Cerebral Ischemia in Rats

The modifying effects of Crocus sativus (CS) stigma extract on neurobehavioral activities, malondialdehyde (MDA), reduced glutathione (GSH), glutathione peroxidase, glutathione reductase, glutathione S-transferase, superoxide dismutase (SOD), catalase (CAT), and Na(+),K(+)-ATPase activities, and glutamate (Glu) and aspartate (Asp) content were examined in the middle cerebral artery (MCA) occlusion (MCAO) model of acute cerebral ischemia in rats. The right MCA of male Wistar rats was occluded for 2 hours using intraluminal 4-0 monofilament, and reperfusion was allowed for 22 hours. MCAO caused significant depletion in the contents of GSH and its dependent enzymes while significant elevation of MDA, Glu, and Asp. The activities of Na(+),K(+)-ATPase, SOD, and CAT were decreased significantly by MCAO. The neurobehavioral activities (grip strength, spontaneous motor activity, and motor coordination) were also decreased significantly in the MCAO group. All the alterations induced by ischemia were significantly attenuated by pretreatment of CS (100 mg/kg of body weight, p.o.) 7 days before the induction of MCAO and correlated well with histopathology by decreasing the neuronal cell death following MCAO and reperfusion. The present results may suggest the effectiveness of CS in focal ischemia most probably by virtue of its antioxidant property.

Dorsal raphe vs. median raphe serotonergic antagonism. Anatomical, physiological, behavioral, neuroendocrinological, neuropharmacological and clinical evidences: relevance for neuropharmacological therapy

Monoaminergic neurons located in the central nervous system (CNS) are organized into complex circuits which include noradrenergic (NA), adrenergic (Ad), dopaminergic (DA), serotonergic (5-HT), histaminergic (H), GABA-ergic and glutamatergic systems. Most of these circuits are composed of more than one and often several types of the above neurons. Such physiologically flexible circuits respond appropriately to both external and internal stimuli which, if not modulated adequately, can trigger pathophysiologic responses. A great deal of research has been devoted to mapping the multiple functions of the CNS circuitry, thereby forming the basis for effective neuropharmacological therapeutic approaches. Such lineal strategies that seek to normalize complex and mixed physiological disorders, however, meet only partial therapeutic success and are often followed by undesirable side effects and/or total failure. In light of these, we have worked to develop possible models of CNS circuitry that are less affected by physiological interaction using the models to design more effective therapeutic approaches. In the present review, we cite and present evidence supporting the dorsal raphe versus median raphe serotonergic circuitry as one model of a reliable paradigm, necessary to the clear understanding and therapy of many psychiatric and even non-psychiatric disturbances.

Long-term use of risperidone in children with disruptive behavior disorders and subaverage intelligence: efficacy, safety, and tolerability

OBJECTIVE

The aim of this study was to assess the long-term efficacy and tolerability of risperidone in the treatment of children and adolescents with disruptive behavior disorder (DBD) and below-average intelligence (IQ < 84) over a cumulative period of 2 years.

METHODS

We followed 48 patients (6-15 years of age), who had previously completed a 1- year open-label study of risperidone, for an additional year of treatment. Efficacy was assessed using the conduct problem subscale of the Nisonger Child Behavior Rating Form (N-CBRF) as a primary outcome measure; other N-CBRF subscales, the Aberrant Behavior Checklist (ABC), and the Clinical Global Impression (CGI) of severity were secondary efficacy measures. Safety and tolerability were also assessed.

RESULTS

Of the 48 patients enrolled in this extension study, 33 (69%) completed the trial. The efficacy benefits from the original study were maintained over the course of the extension study. Safety and tolerability were good overall, with the number of adverse events (AEs) decreasing in the extension trial, compared to the original trial. Six patients (13%) discontinued owing to AEs. Weight gain observed in the original trial stabilized during this extension trial. Cognitive testing demonstrated small, but significant, improvements in cognitive ability.

CONCLUSIONS

Risperidone is safe and effective in treating DBDs in children over a cumulative period of 2 years.

Revisiting the Toxicity of Low-Dose Glucocorticoids: Risks and Fears

We have recently participated in a careful literature search and critical evaluation of glucocorticoids, and we have revised the side-effects data of four recent controlled trials of low-dose glucocorticoids (GCs) in rheumatoid arthritis. The toxicity profile stands out as remarkably more benign than expected from most textbook recommendations. Data regarding low-dose therapy are scarce and of low quality, as no controlled trials have been designed to specifically address toxicity. Common fears of GC toxicity seem to originate from an excessive weight on anecdotal data and observations with high doses, as in organ transplantation. There is now evidence that mechanisms of action of GCs vary considerably according to the dose, thus allowing the possibility of a different toxicity profile. Data from recent controlled trials are quite reassuring, overall. Certainly, risks and benefits of GCs need to be carefully weighed in every patient. But we need to make a clear distinction between established risks and unchecked fears while trying to get the best result for our patient. Clearly, there is a need for studies that are appropriately designed to address the toxicity of GCs and to avoid the risk of "throwing out the baby with the bath water."

Effect of occupational manganese exposure on the central nervous system of welders: 1H magnetic resonance spectroscopy and MRI findings

This study investigated the relationship between long-term occupational manganese (Mn) exposure on the regional Mn concentration in the brain, neuronal loss, and neurobehavioral effects on welders. 1H MRS of the basal ganglia (BG) was performed on 20 male welders and 10 age- and gender-matched, non-office, control workers in a shipyard to assess the metabolic change, and the N-acetylaspartate (NAA)/creatine (Cr), choline (Cho)/Cr and NAA/Cho ratios, by the level of Mn exposure. We also assessed the signal intensity of T1-weighted image of magnetic resonance imaging (MRI) on globus pallidus (GP) compared to that of the frontal white matter (pallidal index, PI). The welders had significantly higher signal intensity than the controls. PI showed a significant dose-response relationship with cumulative exposure index (CEI) (r=0.54, p=0.002). CEI and PI showed different relationships with NAA/Cr according to smoking status, and the correlation was evident only in non-smokers (r=-0.73 and -0.57, respectively). There were no significant differences between the welders and the controls in NAA/Cr, Cho/Cr, and NAA/Cho ratios obtained from BG. CEI was positively correlated with simple reaction time. PI was positively correlated with mean sway (MSWAY), sway area (SWAYA), and sway intensity (SWAYI), and negatively correlated with maximum frequency (MAXF). After categorizing the subjects into two groups according to NAA/Cr ratio level, the low NAA/Cr ratio group showed significantly lower score on digit span backward and significantly higher score on MSWAY, SWAYA and SWAYI in regression analysis than the high NAA/Cr ratio group. We speculated that the NAA/Cr ratio of MRS in BG seems to reflect the cumulative effect of Mn exposure on the human brain. Due to uneven distribution of smoking among the welders and the controls, in addition to the small number of subjects in our study, our findings are needed further studies with a larger number of subjects.

Postnatal methylmercury exposure induces hyperlocomotor activity and cerebellar oxidative stress in mice: dependence on the neurodevelopmental period

During the early postnatal period the central nervous system (CNS) is extremely sensitive to external agents. The present study aims at the investigation of critical phases where methylmercury (MeHg) induces cerebellar toxicity during the suckling period in mice. Animals were treated with daily subcutaneous injections of MeHg (7 mg/kg of body weight) during four different periods (5 days each) at the early postnatal period: postnatal day (PND) 1-5, PND 6-10, PND 11-15, or PND 16-20. A control group was treated with daily subcutaneous injections of a 150 mM NaCl solution (10 ml/kg of body weight). Subjects exposed to MeHg at different postnatal periods were littermate. At PND 35, behavioral tests were performed to evaluate spontaneous locomotor activity in the open field and motor performance in the rotarod task. Biochemical parameters related to oxidative stress (levels of glutathione and thiobarbituric acid reactive substances, as well as glutathione peroxidase and glutathione reductase activity) were evaluated in cerebellum. Hyperlocomotor activity and high levels of cerebellar thiobarbituric acid reactive substances were observed in animals exposed to MeHg during the PND 11-15 or PND 16-20 periods. Cerebellar glutathione reductase activity decreased in MeHg-exposed animals. Cerebellar glutathione peroxidase activity was also decreased after MeHg exposure and the lowest enzymatic activity was found in animals exposed to MeHg during the later days of the suckling period. In addition, low levels of cerebellar glutathione were found in animals exposed to MeHg during the PND 16-20 period. The present results show that the postnatal exposure to MeHg during the second half of the suckling period causes hyperlocomotor activity in mice and point to this phase as a critical developmental stage where mouse cerebellum is a vulnerable target for the neurotoxic and pro-oxidative effects of MeHg.

Our recent experiences with sarin poisoning cases in Japan and pesticide users with references to some selected chemicals

Attention has been paid to neurobehavioral effects of occupational and environmental exposures to chemicals such as pesticides, heavy metals and organic solvents. The area of research that includes neurobehavioral methods and effects in occupational and environmental health has been called "Occupational and Environmental Neurology and Behavioral Medicine." The methods, by which early changes in neurological, cognitive and behavioral function can be assessed, include neurobehavioral test battery, neurophysiological methods, questionnaires and structured interview, biochemical markers and imaging techniques. The author presents his observations of neurobehavioral and neurophysiological effects in Tokyo subway sarin poisoning cases as well as in pesticide users (tobacco farmers) in Malaysia in relation to Green Tobacco Sickness (GTS). In sarin cases, a variety effects were observed 6-8 months after exposure, suggesting delayed neurological effects. Studies on pesticide users revealed that organophosphorus and dithiocarbamate affected peripheral nerve conduction and postural balance; subjective symptoms related to GTS were also observed, indicating the effects of nicotine absorbed from wet tobacco leaves. In addition, non-neurological effects of pesticides and other chemicals are presented, in relation to genetic polymorphism and oxidative stress.

Cannabis et sécurité routière Approche clinique et comportementale

During decades, the detection of alcohol related impairments was the main target for behavioral examination in drivers. The implementation of legislations on illegal drugs and driving, mainly cannabis, has led to an adaptation of the procedures by requiring, from the policemen, an evaluation of external signs of consumption, signs not anymore searched in case of alcohol. The current procedure in France consists in a medical evaluation by a required medical doctor, and based on the Field Sobriety test. This battery was nevertheless established for policemen and used by them in more than 40 countries. A present trend in the French authorities pushes to a back step to a chemical detection of drugs by policemen, by using saliva tests. This approach should have, in their opinion, the advantage of testing drivers without asking them to leave their car for an external evaluation. In our opinion, only a behavioral approach, could help the policemen to have at their disposal, relevant procedures for all situations, especially to face the increasing consumption of cannabis in drivers.

Organophosphate pesticide exposure and neurobehavioral performance in agricultural and non-agricultural Hispanic workers

Our understanding of the health risks of farmworkers exposed to pesticides in their work and home environments is rapidly increasing, although studies designed to examine the possible neurobehavioral effects of low-level chronic pesticide exposure are limited. We measured dialkyl phosphate urinary metabolite levels, collected environmental dust samples from a subset of homes, obtained information on work practices, and conducted neurobehavioral tests on a sample of farmworkers in Oregon. Significant correlations between urinary methyl metabolite levels and total methyl organophosphate (azinphos-methyl, phosmet, malathion) house dust levels were observed. We found the neurobehavioral performance of Hispanic immigrant farmworkers to be lower than that observed in a nonagricultural Hispanic immigrant population, and within the sample of agricultural workers there was a positive correlation between urinary organophosphate metabolite levels and poorer performance on some neurobehavioral tests. These findings add to an increasing body of evidence of the association between low levels of pesticide exposure and deficits in neurobehavioral performance.