Overexcitement and disinhibition. Dynamic neurotransmitter interactions in alcohol withdrawal

Alcohol Withdrawal Syndrome in Women vs Men: Analysis of 1496 Cases at a Single Site

BACKGROUND

Studies of alcohol withdrawal syndrome indicate a higher prevalence in men than in women. However, it is unknown how the condition differs between the sexes.

OBJECTIVE

To assess alcohol withdrawal syndrome in women versus men at a single site.

METHODS

All cases of alcohol withdrawal syndrome at a public hospital from 2010 to 2014 were reviewed retrospectively. For all 1496 episodes, age, sex, and admission to a general care unit (ward) versus the medical intensive care unit were ascertained, along with patient survival. A detailed analysis was performed of 437 cases: all 239 patients admitted to the medical intensive care unit, all 99 female patients admitted to the ward, and 99 randomly selected male patients admitted to the ward. Also analyzed were administration of benzodiazepines, disease course, length of stay, and complications.

RESULTS

Men accounted for 92% of all cases (1378 of 1496; P < .001) and medical intensive care unit admissions (220 of 239; P < .05). Sixteen percent of both men and women were admitted to the medical intensive care unit. Men were older (mean age, 45.6 vs 43.9 years; P < .01), and women required more benzodiazepines. Similar rates of complications occurred in both sexes, although women had a higher rate of pancreatitis and men had higher rates of pneumonia, higher rates of sepsis, and longer stays.

CONCLUSIONS

Men and women with alcohol withdrawal syndrome have similar complications, courses, and intensive care unit admission rates, although men are more prone to pneumonia and have longer stays.

Randomised trial of intravenous thiamine and/or magnesium sulphate administration on erythrocyte transketolase activity, lactate concentrations and alcohol withdrawal scores

Alcohol withdrawal syndrome (AWS) occurs in 2% of patients admitted to U.K. hospitals. Routine treatment includes thiamine and benzodiazepines. Laboratory studies indicate that thiamine requires magnesium for optimal activity, however this has not translated into clinical practice. Patients experiencing AWS were randomized to three groups: (group 1) thiamine, (group 2) thiamine plus MgSO₄ or (group 3) MgSO₄. Pre- and 2-h post-treatment blood samples were taken. AWS severity was recorded using the Glasgow Modified Alcohol Withdrawal Score (GMAWS). The primary outcome measure was 15% change in erythrocyte transketolase activity (ETKA) in group 3. Secondary outcome measures were change in plasma lactate concentrations and time to GMAWS = 0. 127 patients were recruited, 115 patients were included in the intention-to-treat analysis. Pre-treatment, the majority of patients had normal or high erythrocyte thiamine diphosphate (TDP) concentrations (≥ 275–675/> 675 ng/gHb respectively) (99%), low serum magnesium concentrations (< 0.75 mmol/L) (59%), and high plasma lactate concentrations (> 2 mmol/L) (67%). Basal ETKA did not change significantly in groups 1, 2 or 3. Magnesium deficient patients (< 0.75 mmol/L) demonstrated less correlation between pre-treatment basal ETKA and TDP concentrations than normomagnesemic patients (R² = 0.053 and R² = 0.236). Median plasma lactate concentrations normalized (≤ 2.0 mmol/L) across all three groups (p < 0.001 for all groups), but not among magnesium deficient patients in group 1 (n = 22). The median time to achieve GMAWS = 0 for groups 1, 2 and 3 was 10, 5.5 and 6 h respectively (p < 0.001). No significant difference was found between groups for the primary endpoint of change in ETKA. Co-administration of thiamine and magnesium resulted in more consistent normalization of plasma lactate concentrations and reduced duration to achieve initial resolution of AWS symptoms.

ClinicalTrials.gov: NCT03466528.

Alcohol Withdrawal Syndrome in Neurocritical Care Unit: Assessment and Treatment Challenges

Alcohol withdrawal syndrome (AWS) can range from mild jittery movements, nausea, sweating to more severe symptoms such as seizure and death. Severe AWS can worsen cognitive function, increase hospital length of stay, and in-hospital mortality and morbidity. Due to a lack of reliable history of present illness in many patients with neurological injury as well as similarities in clinical presentation of AWS and some commonly encountered neurological syndromes, the true incidence of AWS in neurocritical care patients remains unknown. This review discusses challenges in the assessment and treatment of AWS in patients with neurological injury, including the utility of different scoring systems such as the Clinical Institute Withdrawal Assessment and the Minnesota Detoxification Scale as well as the reliability of admission alcohol levels in predicting AWS. Treatment strategies such as symptom-based versus fixed dose benzodiazepine therapy and alternative agents such as baclofen, carbamazepine, dexmedetomidine, gabapentin, phenobarbital, ketamine, propofol, and valproic acid are also discussed. Finally, a treatment algorithm considering the neurocritical care patient is proposed to help guide therapy in this setting.

On the Neurobiological Role of Oxidative Stress in Alcohol-Induced Impulsive, Aggressive and Suicidal Behavior

Objectives: Alcohol abuse is known to result in behavioral impairments (such as increased impulsivity, aggressive, and suicidal behavior), but the neurobiological basis for these behavioral impairments remains unknown. The objective of this review is to propose a neurobiological basis for alcohol-induced aggression, impulsivity, and suicidal behavior. Methods: Search was done by accessing PubMed/Medline, EBSCO, and PsycINFO databases. The search string used was "(Alcohol OR Alcoholism* OR Alcohol Abuse) AND (Behavior* OR Behavioral Impairment or Disorder) AND (Oxidative Stress OR Reactive Oxygen Species)." The electronic databases were searched for titles or abstracts containing these terms in all published articles between January 1, 1960, and May 31, 2019. The search was limited to studies published in English and other languages involving both animal and human subjects. Articles selected included randomized clinical trials (RCTs), observational studies, meta-analyses, and both systemic and narrative reviews, providing both quantitative and qualitative information with a measure of alcohol abuse or alcoholism as an outcome. Exclusion criteria were unpublished data of any form, including conference proceedings and dissertation. New key terms were identified (new term included: "Antioxidants, Neurotransmitters, Dopamine, Serotonin, GABA, Glutamate. Aggression, Impulsivity, Suicidal Behavior, hippocampus, prefrontal cortex, limbic system, psychiatric disorders, PTSD, Anxiety, Depression. These new terms were searched with Alcohol or Alcoholism or Alcohol Abuse and Oxidative Stress separately resulting in the identification of over 3000 articles. 196 were included in this article. Results: Multiple lines of evidence indicate that oxidative stress (OS) plays a critical underlying role in alcohol toxicity and behavioral impairments. Conclusions/Importance: People diagnosed with PTSD, anxiety disorder, depression, and those with a personality high in psychoticism as measured by the P Scale of the Eysenck Personality Questionnaire, with comorbid alcohol abuse or alcohol use disorder (AUD), may display increased impulsivity, aggression, and suicidal behavior because of the potentiating effect of alcohol-induced OS on their elevated brain oxidative status. Antioxidant therapy should be an integral part of acute alcohol intoxication and AUD treatment. Further research is necessary to fully understand the relationship between OS and alcohol-induced behavioral impairments.

Chronic ethanol exposure induces SK-N-SH cell apoptosis by increasing N-methyl-D-aspartic acid receptor expression and intracellular calcium

It has been identified that chronic ethanol exposure damages the nervous system, particularly neurons. There is scientific evidence suggesting that neuronal loss caused by chronic ethanol exposure has an association with neuron apoptosis and intracellular calcium oscillation is one of the primary inducers of apoptosis. Therefore, the present study aimed to investigate the inductive effects of intracellular calcium oscillation on apoptosis in SK-N-SH human neuroblastoma cells and the protective effects of the N-methyl-D-aspartic acid receptor (NMDAR) antagonist, memantine, on SK-N-SH cell apoptosis caused by chronic ethanol exposure. SK-N-SH cells were treated with 100 mM ethanol and memantine (4 µM) for 2 days. Protein expression of NR1 was downregulated by RNA interference (RNAi). Apoptosis was detected by Annexin V/propidium iodide (PI) double-staining and flow cytometry and cell viability was detected using an MTS kit. Fluorescence dual wavelength spectrophotometry was used to determine the intracellular calcium concentration and the levels of NR1 and caspase-3 were detected using western blotting. NR1 mRNA levels were also detected using qPCR. It was found that chronic ethanol exposure reduced neuronal cell viability and caused apoptosis of SK-N-SH cells, and the extent of damage in SK-N-SH cells was associated with ethanol exposure concentration and time. In addition, chronic ethanol exposure increased the concentration of intracellular calcium in SK-N-SH cells by inducing the expression of NMDAR, resulting in apoptosis, and memantine treatment reduced ethanol-induced cell apoptosis. The results of the present study indicate that the application of memantine may provide a novel strategy for the treatment of alcoholic dementia.

Comparison of Clomethiazole and Diazepam in the Treatment of Alcohol Withdrawal Syndrome in Clinical Practice

BACKGROUND

The objective of this retrospective study was to compare the effectivity and tolerability of diazepam and clomethiazole in the treatment of alcohol withdrawal syndrome (AWS) in a large clinical sample.

METHODS

The data of 566 patients admitted to an intensive care psychiatric unit in Germany (2010-2014) were evaluated. The course of withdrawal was analyzed on a matched sample (n = 152) consisting of a diazepam group (n = 76) and a clomethiazole group (n = 76). Medical assessment was based on a standardized point-based symptom rating scale called AESB (Alkoholentzugssymptom-Bogen), a German modified version of the Revised Clinical Institute Withdrawal Assessment of Alcohol Scale (CIWA-Ar).

RESULTS

Although the mean daily symptom reduction did not differ significantly, patients treated with clomethiazole were treated significantly shorter and needed less concomitant antipsychotic medication. Numbers of complications and adverse events did not show significant differences.

CONCLUSION

Both clomethiazole and diazepam were effective and equally safe in the treatment of AWS. Clomethiazole provided a faster withdrawal and required less concomitant antipsychotic medication and therefore might be the more favorable option for patients and physicians. Taken into account the methodological limitations of the study (retrospective design, secondary matching, missing randomization, use of clomethiazole as drug of first choice), further studies are needed to confirm this result.

Alcohol use disorders and current pharmacological therapies: the role of GABA(A) receptors

Alcohol use disorders (AUD) are defined as alcohol abuse and alcohol dependence, which create large problems both for society and for the drinkers themselves. To date, no therapeutic can effectively solve these problems. Understanding the underlying mechanisms leading to AUD is critically important for developing effective and safe pharmacological therapies. Benzodiazepines (BZs) are used to reduce the symptoms of alcohol withdrawal syndrome. However, frequent use of BZs causes cross-tolerance, dependence, and cross-addiction to alcohol. The FDA-approved naltrexone and acamprosate have shown mixed results in clinical trials. Naltrexone is effective to treat alcohol dependence (decreased length and frequency of drinking bouts), but its severe side effects, including withdrawal symptoms, are difficult to overcome. Acamprosate showed efficacy for treating alcohol dependence in European trials, but two large US trials have failed to confirm the efficacy. Another FDA-approved medication, disulfiram, does not diminish craving, and it causes a peripheral neuropathy. Kudzu is the only natural medication mentioned by the National Institute on Alcohol Abuse and Alcoholism, but its mechanisms of action are not yet established. It has been recently shown that dihydromyricetin, a flavonoid purified from Hovenia, has unique effects on GABAA receptors and blocks ethanol intoxication and withdrawal in alcoholic animal models. In this article, we review the role of GABAA receptors in the treatment of AUD and currently available and potentially novel pharmacological agents.

Factor Structure of CIWA-Ar in Alcohol Withdrawal

Objective. To identify the underlying factor structure of alcohol withdrawal syndrome, as measured with CIWA-Ar. Methods. Exploratory factor analysis was conducted on the items of CIWA-Ar. On 201 alcohol-dependent male patients seeking treatment for alcohol withdrawal at 36 hours of abstinence. Results. A three-factor solution was obtained that accounted for 68.74% of total variance. First factor had loading from four items (34.34% variance), second factor also had four items (24.25% variance), and the third had two items (10.04% variance). Conclusions. Factor analysis reveals the existence of multidimensionality of alcohol withdrawal as measured with CIWA-Ar and we found three factors that can be named as delirious, autonomic and nonspecific factors.

A heuristic model of alcohol dependence

Background

Substance dependence poses a critical health problem. Sadly, its neurobiological mechanisms are still unclear, and this lack of real understanding is reflected in insufficient treatment options. It has been hypothesized that alcohol effects are due to an imbalance between neuroexcitatory and neuroinhibitory amino acids. However, glutamate and GABA interact with other neurotransmitters, which form a complicated network whose functioning evades intuition and should be investigated systemically with methods of biomedical systems analysis.

Methods and Results

We present a heuristic model of neurotransmitters that combines a neurochemical interaction matrix at the biochemical level with a mobile describing the balances between pairs of neurotransmitters at the physiological and behavioral level. We investigate the effects of alcohol on the integrated neurotransmitter systems at both levels. The model simulation results are consistent with clinical and experimental observations. The model demonstrates that the drug diazepam for symptoms of alcohol withdrawal effectively reduces the imbalances between neurotransmitters. Moreover, the acetylcholine signal is suggested as a novel target for treatment of symptoms associated with alcohol withdrawal.

Conclusions

Efficient means of integrating clinical symptoms across multiple levels are still scarce and difficult to establish. We present a heuristic model of systemic neurotransmitter functionality that permits the assessment of genetic, biochemical, and pharmacological perturbations. The model can serve as a tool to represent clinical and biological observations and explore various scenarios associated with alcohol dependence and its treatments. It also is very well suited for educational purposes.

Alcohol, nicotine, and iatrogenic withdrawals in the ICU

OBJECTIVES

The neurophysiology, risk factors, and screening tools associated with alcohol withdrawal syndrome in the ICU are reviewed. Alcohol withdrawal syndrome assessment and its treatment options are discussed. Description of nicotine withdrawal and related publications specific to the critically ill are also reviewed. A brief comment as to sedative and opiate withdrawal follows.

DATA AND SUMMARY

The role of currently published alcohol withdrawal syndrome pharmacologic strategies (benzodiazepines, ethanol, clomethiazole, antipsychotics, barbiturates, propofol, and dexmedetomidine) is detailed. Studies on nicotine withdrawal management in the ICU focus mainly on the safety (mortality) of nicotine replacement therapy. Study characteristics and methodological limitations are presented.

CONCLUSION

We recommend a pharmacologic regimen titrated to withdrawal symptoms in ICU patients with alcohol withdrawal syndrome. Benzodiazepines are a reasonable option; phenobarbital appears to confer some advantages in combination with benzodiazepines. Propofol and dexmedetomidine have not been rigorously tested in comparative studies of drug withdrawal treatment; their use as additional or alternative strategies for managing withdrawal syndromes in ICU patients should therefore be individualized to each patient. Insufficient data preclude recommendations as to nicotine replacement therapy and management of iatrogenic drug withdrawal in ICU patients.

Substitution therapy for alcoholism: time for a reappraisal?

A number of compounds already in use as medications for various indications substitute for ethanol at clinically relevant brain pathways, in particular, at gamma-aminobutyric acid (GABA) receptors. Nevertheless, although substitute medications have been recognized for heroin and tobacco dependence, patients with alcohol dependence are rarely offered an analogous approach. Benzodiazepines may have paradoxical effects, and abuse and dependence are known. Baclofen (GABA(B) agonist) has not been associated with dependence or misuse and has been effective in several trials in preventing relapse, although research is required to establish the optimal dosing regimen. GABA-ergic anticonvulsants, helpful in treating withdrawal, have yet to emerge as effective in relapse prevention. Clomethiazole and sodium oxybate, the latter having been shown to be effective in relapse prevention, have incurred a reputation for dependence and abuse. However, data have emerged showing that the risk of abuse of sodium oxybate is lower than many clinicians had foreseen. For a condition where existing therapies are only effective in a proportion of patients, and which has high morbidity and mortality, the time now seems right for reappraising the use of substitute prescribing for alcohol dependence.

Epileptiform activity in alcohol dependent patients and possibilities of its indirect measurement

Background

Alcohol dependence during withdrawal and also in abstinent period in many cases is related to reduced inhibitory functions and kindling that may appear in the form of psychosensory symptoms similar to temporal lobe epilepsy frequently in conditions of normal EEG and without seizures. Because temporal lobe epileptic activity tend to spread between hemispheres, it is possible to suppose that measures reflecting interhemispheric information transfer such as electrodermal activity (EDA) might be related to the psychosensory symptoms.

Methods and Findings

We have performed measurement of bilateral EDA, psychosensory symptoms (LSCL-33) and alcohol craving (ACQ) in 34 alcohol dependent patients and 32 healthy controls. The results in alcohol dependent patients show that during rest conditions the psychosensory symptoms (LSCL-33) are related to EDA transinformation (PTI) between left and right EDA records (Spearman r = 0.44, p<0.01).

Conclusions

The result may present potentially useful clinical finding suggesting a possibility to indirectly assess epileptiform changes in alcohol dependent patients.

Abrupt termination of an ethanol regimen provokes ventricular arrhythmia and enhances susceptibility to the arrhythmogenic effects of epinephrine in rats

BACKGROUND

Pathologists examining victims of sudden unexpected death encounter alcoholics more often than expected; alcohol may play a role in sudden arrhythmic death. Here we determine whether a pattern of alcohol consumption, chronic ethanol intake, and withdrawal increases the incidence of malignant ventricular arrhythmia and modulates susceptibility to the arrhythmogenic potential of sympathetic stimulation from an epinephrine test in rats.

METHODS

Male Wistar rats were treated with a continuous ethanol liquid diet for 7 weeks, and then subjected to 1-day withdrawal or 21-day abstinence. Ventricular ectopy was evaluated by 24-hour electrocardiographic telemetry recording; whole-body sympathetic activation, cardiac sympathovagal balance, and susceptibility to ventricular arrhythmia induced by sympathetic stimulation were evaluated based on blood noradrenalin metabolite concentrations, heart rate variability, and a 3-step epinephrine test.

RESULTS

Ventricular arrhythmia and related death were observed only in rats at 1 day of withdrawal, but not in nonalcoholic, continuous ethanol intake or 21-day abstinence rats. One-day withdrawal after a 7-week continuous ethanol regimen elevated circulating noradrenalin metabolite levels and induced cardiac sympathovagal imbalance. Deaths related to the epinephrine test and ventricular arrhythmia induced by low doses of epinephrine were observed only in 1-day withdrawal rats. However, all anomalies were normalized by 21-day abstinence.

CONCLUSIONS

Abrupt termination of a 7-week continuous ethanol regimen is sufficient to enhance the whole-body sympathetic activation and cardiac sympathovagal imbalance that contribute to ventricular arrhythmia and sudden death in alcoholic rats. Those providing medical care for alcoholics, including in cases of legal imprisonment, should be aware of the possibility of enhanced susceptibility to sudden arrhythmic death due to the abrupt termination of a chronic ethanol regimen.

The 3' part of the dopamine transporter gene DAT1/SLC6A3 is associated with withdrawal seizures in patients with alcohol dependence

BACKGROUND

Some studies have reported that the A9 allele of the variable nucleotide tandem repeat (VNTR) of the gene which encodes the dopamine transporter (DAT1/SLC6A3) is associated with alcoholism withdrawal symptoms such as alcohol withdrawal seizures (WSs), whereas others did not. We investigated whether polymorphisms within the DAT1 gene are associated with WS taking into account some of the confounding factors such as the severity of alcohol dependence.

METHODS

To further assess the role of this gene in WS, we genotyped the VNTR and 7 single nucleotide polymorphisms (SNPs) encompassing the DAT1 gene in a sample of 250 alcohol-dependent subjects (175 men and 75 women), of whom 24% exhibited WSs, taking into account the severity of alcohol dependence.

RESULTS

The VNTR is associated with an increased risk of WSs (odd ratio = 3.5; p = 0.019), even when controlling for confounding factors (p = 0.031). As 2 SNPs, in roughly the same location of the gene (namely rs27072 and rs27048), are also associated with WSs, it is possible that the initial association of the VNTR polymorphism was tagging a specific haplotype of this gene. Indeed, in our sample of alcohol-dependent patients, 2 haplotypes were associated with a significantly different risk of WSs.

CONCLUSIONS

The present study adds evidence for a significant role of the 3' part of the DAT1 gene in WS of alcohol-dependent patients, not only because it is in accordance with previous work, but also because of larger statistical power (as relying on a sample over sampled with the studied phenotype), as it gives a more precise analysis of different SNPs within the DAT1 gene, and as it confirms the association when major potentially confounding factors are taken into account in a logistical regression analysis.

Can mismatch negativity be linked to synaptic processes? A glutamatergic approach to deviance detection

This article aims to provide a theoretical framework to elucidate the neurophysiological underpinnings of deviance detection as reflected by mismatch negativity. A six-step model of the information processing necessary for deviance detection is proposed. In this model, predictive coding of learned regularities is realized by means of long-term potentiation with a crucial role for NMDA receptors. Mismatch negativity occurs at the last stage of the model, reflecting the increase in free energy associated with the switching on of silent synapses and the formation of new neural circuits required for adaptation to the environmental deviance. The model is discussed with regard to the pathological states most studied in relation to mismatch negativity: alcohol intoxication, alcohol withdrawal, and schizophrenia.

The Effect of Curcumin on Ethanol Induced Changes in Suprachiasmatic Nucleus (SCN) and Pineal

(1) Circadian clocks have been localized to discrete sites within the nervous system of several organisms and in mammals to the suprachiasmatic nucleus (SCN) in the anterior hypothalamus. The SCN controls and regulates the production and discharge of melatonin (hormonal message of darkness) from the pineal gland via a multisynaptic efferent pathway. The nocturnal rise in melatonin production from serotonin results due to an increased activity of serotonin N-acetyl transferase (NAT). (2) The complex interaction between alcohol and biological clock need to be understood as alcoholism results in various clock linked neuronal disorders especially loss of memory and amnesia like state of consciousness, sleep disorders, insomnia, dementia etc. (3) Serotonin, 5-Hydroxy-tryptamine (5-HT) plays an important role in mediating alcohol's effects on the brain. Understanding the impact of alcohol consumption on circadian system is a pre-requisite to help in treatment of alcohol induced neurological disorders. We, therefore, studied the effect of ethanol drinking and ethanol withdrawal on daily rhythms of serotonin and its metabolite, 5-hydroxy-indole acetic acid (5-HIAA) in SCN and Pineal of adult male Wistar rats maintained under light-dark (LD, 12:12) conditions. (4) Curcumin is well known for its protective properties such as antioxidant, anti-carcinogenic, anti-viral and anti-infectious etc. Hence, we studied the effect of curcumin on ethanol induced changes on 5-HT and 5-HIAA levels and rhythms in SCN and Pineal. (5) Ethanol withdrawal could not restore either rhythmicity or phases or levels of 5-HT and 5-HIAA. Curcumin administration resulted in partial restoration of daily 5-HT/5-HIAA ratio, with phase shifts in SCN and in Pineal. Understanding the impact of alcohol consumption on circadian system and the role of herbal medication on alcohol withdrawal will help in treatment of alcohol induced neurological disorders.

Bench-to-bedside review: critical illness-associated cognitive dysfunction--mechanisms, markers, and emerging therapeutics

Cognitive dysfunction is common in critically ill patients, not only during the acute illness but also long after its resolution. A large number of pathophysiologic mechanisms are thought to underlie critical illness-associated cognitive dysfunction, including neuro-transmitter abnormalities and occult diffuse brain injury. Markers that could be used to evaluate the influence of specific mechanisms in individual patients include serum anticholinergic activity, certain brain proteins, and tissue sodium concentration determination via high-resolution three-dimensional magnetic resonance imaging. Although recent therapeutic advances in this area are exciting, they are still too immature to influence patient care. Additional research is needed if we are to understand better the relative contributions of specific mechanisms to the development of critical illness-associated cognitive dysfunction and to determine whether these mechanisms might be amenable to treatment or prevention.

Genetic Polymorphisms Related to Delirium Tremens: A Systematic Review

BACKGROUND

Delirium tremens (DT) is one of the more severe complications of alcohol withdrawal (AW), with a 5 to 10% lifetime risk for alcohol-dependent patients. The 2 most important neurosystems involved in AW are gamma-aminobutyric acid and glutamate. It is unknown whether these neurosystems are involved in the pathophysiology of DT as well. The candidate gene approach in DT could contribute to this knowledge and demonstrate a possible genetic predisposition for DT. The purpose of this study is to give an overview of all studied genetic polymorphisms in the diverse candidate genes related to DT and to summarize what these studies contribute to insights into the pathophysiology of DT.

METHODS

The inclusion criteria for this literature study were articles in English analyzing the association between a genetic polymorphism and DT without other AW syndromes. Studies were identified until February 2006 in MEDLINE and EMBASE databases.

RESULTS

We found 25 studies dealing with 30 polymorphisms, located in 19 different genes. Positive associations were found in 3 different candidate genes involved in the dopamine transmission, 1 gene involved in the glutamate pathway, 1 neuropeptide gene, and 1 cannabinoid gene. Two candidate genes involved in the dopamine transmission, dopamine receptor D3, and solute carrier family 6, were each associated with DT in 2 different study populations. The other 4 positive associations were not replicated in other studies.

CONCLUSIONS

A total of 8 positive associations out of 30 polymorphisms makes a genetic base for DT plausible. Understanding the pathophysiological process of the development of DT has, indeed, been augmented by the reviewed genetic association studies. These studies suggest that the regulation of dopaminergic neurotransmission may play an important role.

[Carbamazepine intoxication. Complication of alcohol detoxification with combined carbamazepine and tiapride]

The advantages of alcohol detoxification treatment with combined carbamazepine and tiapride compared to benzodiazepines or clomethiazole is a lower level of sedation and lack of addictive potential. We report a case of carbamazepine intoxication with serum levels up to 19 mg/l in an otherwise healthy 45-year-old alcohol-dependent male after treatment with 600 mg carbamazepine and 600 mg tiapride per day. Medication was discontinued immediately and a purgative was administered. We were able to combat the intoxication but the assumed good tolerance of the combined treatment with carbamazepine and tiapride for alcohol detoxification still has to be proven.

Individual differences in ethanol self-administration following withdrawal are associated with asymmetric changes in dopamine and serotonin in the medial prefrontal cortex and amygdala

BACKGROUND

Ethanol withdrawal alters brain neurochemistry, causes asymmetric activation of neurons in the medial prefrontal cortex (mPFC) and amygdala (AMY), and increases ethanol craving and drinking. Rats with intrinsic rightward-turning preferences drink more ethanol than those with left or no preferences; they also exhibit an ethanol-induced neurochemical activation that favors the right side of the mPFC. Our experiments used rats with different turning preferences to assess differences in withdrawal effects on mPFC and AMY neurochemistry as well as ethanol self-administration.

METHODS AND RESULTS

Rats with left-turning, right-turning, and nonturning preferences were fed a 6% ethanol-containing liquid diet (WD) or a pair-fed control diet for 14 days. Differences in dopamine (DA), serotonin (5HT), norepinephrine (NE), and metabolite [3,4-dihydroxphenylacetic acid, homovanillic acid (HVA), and 5-hydroxyindoleacetic acid) concentrations were assessed in each side of the mPFC and AMY during acute withdrawal. Similar groups were fed the same diets and tested for consumption of 10% ethanol versus water and 1% sucrose versus water. WD increased HVA/DA in the mPFC and caused depletions of DA and 5HT in the mPFC and 5HT in the AMY. These effects were greater in the right than in the left side of these structures in rats with right-turning preferences. WD reduced ethanol drinking but right turners drank significantly more than left turners on day 2 of testing and drank more on days 2 and 3 than on day 1. No effects were observed on sucrose drinking. Similar groups were also trained to self-administer ethanol using a sucrose-fade sipper tube procedure that separated measures of ethanol seeking (bar pressing) and consumption. Following 14 days of vapor chamber exposure to ethanol, rats of all turning preferences had a lower rate of bar pressing on the first postwithdrawal day and shorter latencies to begin bar pressing on the third withdrawal day versus prewithdrawal baseline. Only right-turning-preference rats consumed more ethanol following withdrawal.

CONCLUSIONS

These studies show that individual rats differ in postwithdrawal brain neurochemistry and ethanol consumption and that these differences are associated with differences in functional brain asymmetry.

Treatment of alcohol withdrawal syndrome with a combination of tiapride/carbamazepine: results of a pooled analysis in 540 patients

This was a retrospective study to examine the efficacy, practicability and medical safety of a combination of tiapride and unretarded (fast acting formula) carbamazepine in the treatment of alcohol withdrawal syndrome. In five hospitals using this combination for treatment of alcohol withdrawal, 540 patients who had been treated with this combination were identified. An intensive evaluation of patients files and charts was performed. Details of alcohol history and comorbid disorders were extracted from patient files. Severity of alcohol withdrawal had been assessed using the CIWA-A-Score. Gender differences and differences between patients in their first and at least second withdrawal were computed by means of variance analyses (GLM). At baseline (day 1) mean dosage given was 796 for tiapride and 543 mg for carbamazepine. A pooled analysis of the results showed that, in general, medication was well tolerated. Withdrawal symptomatology as indicated by CIWA-A scores clearly decreased over time. Although a significant number of patients had a history of alcohol withdrawal delirium (103) and epileptic seizures (151), few patients suffered from them during treatment (8 and 5, respectively). Only 24 (4.4%) patients dropped out because of lack of efficacy or change of medication, 15 (2.8%) because of side effects. No case of malignant neuroleptic syndrome was recorded. Data analysis showed gender differences and differences between patients in their first and at least second withdrawal for side effects, complications, and in some CIWA-A-scores. In general, severe complications of withdrawal syndrome were more frequent in men compared to women and in patients with repeated inpatient treatment. In line with previous research, the results from this study give further evidence that a combination of the anticonvulsant carbamazepine and tiapride is an effective and safe treatment for alcohol withdrawal treatment.

Double-blind study of cyamemazine and diazepam in the alcohol withdrawal syndrome

OBJECTIVE

Cyamemazine is an original phenothiazine derivative which showed similar efficacy and tolerability to lorazepam during ethanol withdrawal in mice. This study investigated cyamemazine for its efficacy and tolerability in alcohol-dependent patients electing an alcohol withdrawal procedure, in comparison with diazepam.

METHOD

A multicenter, randomized, double-blind study in 89 alcohol-dependent patients (CIWA-Ar score between 10 and 30), electing an alcohol withdrawal procedure, was used to find effective doses of cyamemazine and to compare it with diazepam for efficacy and tolerability. On day 1 (D(1)), cyamemazine or diazepam (50 mg and 10 mg capsule, respectively) were administered at hourly intervals to reduce CIWA-Ar = 5, up to a maximum of eight administrations. Starting from D(2), the compounds were given twice a day in progressively decreasing doses during a maximum period of 13 days (D(end)).

RESULTS

At h(8) (8 h after the first treatment of D(1)), therapeutic success (CIWA-Ar score </= 5) was achieved in 32 out of 43 ITT patients treated with cyamemazine (74.4%), a value very similar to that of diazepam (32/44; 72.7%). Most such patients (29/32) were controlled with 2-6 capsules of cyamemazine (100-300 mg). In the PP population, cyamemazine (n = 28) was significantly non-inferior to diazepam (n = 33), with a threshold of 10% for non-inferiority bound and 2.5% for one-sided type I error rate. Such therapeutic similarity was confirmed by the analysis of other efficacy criteria. Safety analysis did not show substantial differences between the two treatments.

CONCLUSIONS

Cyamemazine showed similar efficacy and tolerability to diazepam for the treatment of alcohol withdrawal symptoms at therapeutic doses in the range 100-300 mg.

UPREGULATION OF GLUTAMATE RECEPTOR SUBTYPES DURING ALCOHOL WITHDRAWAL IN RATS

AIMS

To investigate glutamate receptor subtypes during alcohol withdrawal.

METHODS

Rats were exposed to severe alcohol intoxication for 84 h and then decapitated at 0, 12 and 36 h after the last alcohol dose (n = 7 per group). Alcohol was administered five times a day by intragastric intubation. The densities of N-methyl-D-aspartate (NMDA) and 2-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors were studied in membranes from the forebrain by using the specific ligands [3H]MK-801 and [3H]AMPA, respectively.

RESULTS

Although no change in the maximal density (B(max)) of [3H]MK-801 binding sites was observed at the time of withdrawal, [3H]MK-801 binding was increased by 49% 12 h into the withdrawal reaction compared with the control group. At 36 h post alcohol the B(max) of the [3H]MK-801 binding was still increased by 24% compared with the control group; however, this difference was not statistically significant. When investigated at the time of withdrawal from chronic alcohol intoxication, no significant alterations in the B(max) of the [3H]AMPA binding was detected, but 12 h into the withdrawal reaction the [3H]AMPA binding was markedly increased by 94%. At 36 h post alcohol the [3H]AMPA binding had returned to control levels. No significant alterations in the dissociation constant (K(D)) of either [3H]MK-801 or [3H]AMPA binding was observed at any time point.

CONCLUSIONS

NMDA and AMPA receptors are involved in the cerebral hyperactivity of alcohol withdrawal.

Magnesium Treatment of Primary Alcohol-Dependent Patients During Subacute Withdrawal: An Open Pilot Study With Polysomnography

BACKGROUND

Sleep electroencephalogram alterations and insomnia complaints persist after alcohol withdrawal in dependent patients and are considered strong predictors of relapse. Although disturbances of magnesium household due to alcohol consumption are well known, the relationship of magnesium metabolism and sleep disturbances has not been investigated in this patient group. We conducted an open pilot study to evaluate the effects of magnesium treatment on the sleep of primary alcohol-dependent patients during subacute withdrawal.

METHODS

Patients were treated with 30 mmol magnesium daily over 4 weeks. Eleven of the 14 included patients were evaluated. Patients were free of any kind of psychotropic medication or other substances known to influence sleep. Polysomnographic recordings with monitoring of periodic leg movements in sleep (PLMS) were performed for two consecutive nights 2 weeks after acute withdrawal (baseline) and 4 weeks later at the end of the treatment period. After the baseline polysomnography, patients were investigated by the magnesium loading test to verify magnesium depletion.

RESULTS

We found a significant decrease of sleep onset latency from 40.6 to 21.7 min (p = 0.03) and a significant improvement of subjective sleep quality, as assessed by the Pittsburgh Sleep Quality Index, from 8.1 to 5.8 (p = 0.05) during magnesium treatment. Changes in PLMS indices revealed two subgroups of patients: one with an increase of PLMS from 30.7 to 39.4 per hour of sleep (n = 4) and the other one with a decrease of PLMS from 8.9 to 2.1 per hour of sleep (p = 0.04). Patients with PLMS decreases seemed to have a more favorable prognosis: total sleep time, gamma-glutamyltransferase, carbohydrate-deficient transferrin, and Beck Depression Inventory scores improved significantly during treatment in this group. The magnesium loading test revealed a magnesium deficiency in only one patient, five patients showed normal retention values, and the remaining five patients had an increased magnesium excretion, indicating a possible continued renal magnesium loss during abstinence.

CONCLUSIONS

The results of this study should be interpreted with caution, because no control group with placebo was investigated. Both subjective and, partly, objective parameters of sleep improved during the 4-week study period. Further research is needed to clarify the relationship of magnesium metabolism and sleep alterations.

Mechanisms of cardiovascular dysregulation during alcohol withdrawal

Alcohol withdrawal (AW) is often accompanied by functional cardiovascular abnormalities which return to normal in few days. However, in some patients, they can predict future alterations in the cardiovascular system, even if they remain in abstinence. These changes are mediated by several central and peripheral mechanisms closely related to AW. The level of activation in the sympathetic nervous system is an important factor regulating the functioning of the cardiovascular system in AW directly and/or indirectly with L-type calcium channels and nitric oxide (NO). Other factors may contribute to cardiovascular alterations in AW including the renin-angiotensin-aldosterone system, vasopressin, cortisol and sodium sensitivity. Monitoring of the cardiovascular system is needed in patients undergoing treatment for AW. The patients with elevated systolic blood pressure (SBP) and diastolic blood pressure (DBP) after resolution of AW may require a fuller work-up of their cardiovascular system.

Estimation of endogenous noradrenaline release in rat brain in vivo using [3H]RX 821002

Noradrenaline plays an important role in many normal brain functions, e.g., attention, memory, and emotion. Dysfunction in the noradrenergic system is thought to lead to a number of abnormal brain conditions. The lack of suitable in vivo tracers to monitor noradrenaline release, levels, and regulation has hampered our fully understanding the roles that it plays in the brain. Presented here are data showing that the in vivo binding of the alpha2-adrenoceptor antagonist [3H]RX 821002 is sensitive to endogenous noradrenaline. Elevation of extracellular noradrenaline, using three different pharmacological challenges in rat, led to a reduction in the binding potential (BP) of [3H]RX 821002 when compared with vehicle controls. The challenges used were i.p. administration of D-amphetamine, the imidazoline2 binding site-selective ligand BU224, and L-deprenyl. Of the cortical regions measured, the reduction in BP reached significance in the anterior cingulate cortex for all of these pharmacological challenges. These initial observations in rat indicate that labelling of the alpha2-adrenoceptors with RX 821002 can be used to estimate changes in extracellular noradrenaline concentration in the cortex. This has the potential to enable the investigation of the role that noradrenaline plays both in the normal and abnormal brain and, if the ligand can be radiolabelled with a suitable positron-emitting isotope at high specific radioactivity, it could be an invaluable PET tracer.

Alcohol and withdrawal: from animal research to clinical issues

The withdrawal syndrome in alcohol-dependent patients appears to be a major stressful event whose intensity increases with repetition of detoxifications according to a kindling process. Disturbances in the balance between excitatory and inhibitory neural processes are reflected in a perturbed physical state while disturbances in the balance between positive and negative reinforcements are reflected in a perturbed mood state. Our purpose is to link the different behavioral outcomes occurring during withdrawal with specific biological brain mechanisms from the animal to the human being. Better understanding of the various biological mechanisms underlying withdrawal from alcohol will be the key to design and to apply appropriate pharmaceutical management, together with appropriate therapy aimed at inducing protracted abstinence.

Association of a CB1 cannabinoid receptor gene (CNR1) polymorphism with severe alcohol dependence

Due to the involvement of the endogenous cannabinoid system in brain reward mechanisms a silent polymorphism (1359G/A; Thr453Thr) in the single coding exon of the CB1 human cannabinoid receptor gene (CNR1) was analysed in 121 severely affected Caucasian alcoholics and 136 most likely non-alcoholic controls. The observed frequency of the A allele was 31.2% for controls and 42.1% for alcoholics with severe withdrawal syndromes (P=0.010). Post-hoc exploration indicated that this allelic association resulted from an excess of the homozygous A/A genotype in patients with a history of alcohol delirium (P=0.031, DF 2), suggesting s an increased risk of delirium (OR=2.45, 95% CI 1.14--5.25). This finding suggests that the homozygous genotype CNR1 1359A/A confers vulnerability to alcohol withdrawal delirium.

A Short Alcohol Withdrawal Scale (SAWS): development and psychometric properties

The measurement of alcohol withdrawal symptoms is important for the assessment of the alcohol withdrawal syndrome and for the evaluation of the effectiveness of withdrawal treatment interventions. There continues to be a need for an instrument for the measurement of alcohol withdrawal severity which is short, easy to understand (especially by respondents who may feel anxious, confused or physically ill) and easy to administer (for example, within clinical services with limited time and resources).This paper describes the development and psychometric properties of the 10-item Short Alcohol Withdrawal Scale. The SAWS includes five items which represent psychological symptoms (anxious, confused, restless, miserable, memory problems) which accounted for 47% of the variance. A further five items represent physical symptoms (tremor, nausea, heart pounding, sleep disturbance, sweating) and accounted for 11% of the variance. The procedures leading to the development of the scale are described and results are presented showing that the SAWS has high internal consistency, and good construct and concurrent validity.

Cation modulation of GABA(A) receptors in brain sections of AT and ANT rats

Changes in magnesium ion (Mg(2+)) concentration may be implicated in alcohol-related behaviors through modulation of neuronal excitability by actions on ligand-gated ion channels. To study whether putative Mg(2+)-binding sites differ between two rat lines, alcohol-insensitive (AT) and alcohol-sensitive (ANT) rats, selectively outbred for differential sensitivity to the motor-impairing effect of ethanol, we compared the effect of Mg(2+) on [35S]tert-butylbicyclophosphorothionate ([35S]TBPS) binding to GABA(A) receptors with the use of ligand autoradiographic analyses of brain sections from these rats. There were some slight differences between the rat lines in modulation of the binding in the forebrain. A low concentration of Mg(2+) (0.1 mM) inhibited basal [35S]TBPS binding more efficiently in the central gray matter and hippocampus in the ANT rats than in the AT rats. In the presence of gamma-aminobutyric acid, the effect of a low concentration of Mg(2+) was higher in the caudate-putamen and inner layer of the cerebral cortex in the AT rats than in the ANT rats. No difference between the rat lines was found at a higher (3 mM) Mg(2+) concentration. Furosemide, a GABA(A) antagonist selective for cerebellar granule cell-specific alpha6beta2/3 subunit-containing receptors, was less efficient in antagonizing the Mg(2+)-induced inhibition of [35S]TBPS binding in the ANT rats than in the AT rats. Another divalent cation, zinc ion, was less efficient in displacing [35S]TBPS binding from the cerebellar granule cell layer in the ANT rats than in the AT rats, whereas a trivalent cation, lanthanum ion, produced identical modulation of the binding in the two rat lines. The results indicate that the alcohol-sensitive ANT rats have altered cerebellar granule cell--specific alpha6 subunit--containing GABA(A) receptors and seem to indicate that these receptors might be implicated in the sensitivity difference of the rat lines to ethanol and sedative drugs.

Importance of magnesium ions in development of tolerance to ethanol: studies on cultured cerebral vascular smooth muscle cells, type-2 astrocytes and intact rat brain

This study was designed to examine the roles of intracellular free magnesium ion concentration ([Mg(2+)](i)) in ethanol-induced intoxication and development of tolerance in cultured canine cerebral vascular smooth muscle cells and astrocytes as well as intact rat brain. The basal, resting level of [Mg(2+)](i) in cerebrovascular cells was 732.5 +/- 82.4 microM. Exposure of cultured canine cerebral vascular smooth muscle cells to ethanol (10 and 25 mM) for 24 h reduced the concentrations of [Mg(2+)](i) to 521.1 +/- 59.6 microM, and 308.2 +/- 37.8 microM, respectively. However, exposure of these cultured vascular cells to the same concentrations of ethanol, after initial pretreatment with ethanol for 24 h, failed to interfere with the levels of [Mg(2+)](i). Measurement of [Mg(2+)](i) at 48 h and 72 h indicated that the decreased levels of [Mg(2+)](i) induced by ethanol at 24 h treatment returned toward baseline. Similar experiments were performed in cultured type-2 astrocytes isolated from neonatal rat brain. The basal level of [Mg(2+)](i) in type-2 astrocytes was about 125 microM. Incubation of these cells with 10 mM ethanol for 10 min resulted in a 27% reduction in the level of [Mg(2+)](i), whereas incubation with 25 mM ethanol resulted in almost a 50% reduction in [Mg(2+)](i). The decreased levels of [Mg(2+)](i) lasted around 30 min, until the measurement finished. Continuous incubation of these cultured astrocytes, with ethanol (either 10 mM or 25 mM), for more than 24 h, indicated that the concentrations of [Mg(2+)](i) in type-2 astrocytes were equivalent to those at basal, resting levels. In vivo 31P-NMR spectroscopy, performed on intact rat brains, indicated that an initial administration of 4 mg/kg ethanol ( approximately 20-25 mM blood alcohol level) resulted (after 20-40 min of exposure) in severe deficits in whole brain [Mg(2+)](i) (550 +/- 33 microM to 358 +/- 24 microM). Repeated injections of ethanol (4 mg/kg) over the next 24-72 h resulted in progressively diminishing effects on brain [Mg(2+)](i). These experimental data indicate that chronic ethanol treatment can induce a tolerance to depletion of [Mg(2+)](i) in cerebrovascular smooth muscle cells, type-2 astrocytes as well as intact rat brain. The results suggest that [Mg(2+)](i) might play a major role in alcohol-induced tolerance in the brain.

Psychopathology of alcoholics during withdrawal and early abstinence

Epidemiologic surveys show a high lifetime co-morbidity with psychiatric disorders (e.g., depression and anxiety) in alcoholics. However, alcoholics frequently complained about psychopathologic symptoms, particularly during alcohol withdrawal. There is some evidence that symptomatology decreases spontaneously with prolonged abstinence. Thus, the question arises whether high levels of psychopathology could be accounted for by withdrawal effects. This study was aimed at examining the impact of the alcohol withdrawal severity (assessed by the AWS scale) on psychopathologic symptoms. The psychopathologic profile of 110 alcoholics as measured by the Symptom Checklist-90 revised (SCL-90-R) was compared to that of 253 patients with adjustment, anxiety or depressive disorders (according to ICD-10 criteria). No relationship between the severity of alcohol withdrawal and psychopathology could be found which might hint at two different neurobiological processes underlying these phenomena. The comparison with patients suffering from depression or anxiety disorders revealed that the global symptom severity of alcoholics undergoing withdrawal was similar, but recovery was achieved more rapidly than in the other groups. On the other hand, the self-rated psychopathologic symptom profile of alcoholics was rather similar to that of patients with adjustment disorders. While about one-quarter of the alcoholics reported severe psychopathology on admission, only about 10% showed symptomatology at discharge about three weeks later, predominantly depression or anxiety. These results underline the notion that much of the psychopathology described by alcoholics decreases within 2-3 weeks after withdrawal without specific treatment.

Impact of substance abuse on the course and treatment of bipolar disorder

OBJECTIVES

The objectives of this article are to review the prevalence, natural history, pathophysiology, and treatment of comorbid bipolar disorder with alcoholism and other psychoactive substance use disorders (PSUDs).

METHODS

All identified bibliographies through a literature search of all Medline files and bibliographies of selected articles focusing on the prevalence, natural history, course, prognosis, inter-relationship, and treatment of bipolar disorder with comorbid alcoholism and other PSUDs were reviewed.

RESULTS AND CONCLUSIONS

Comorbidity of bipolar disorder and alcoholism and other PSUDs is highly prevalent. The presence of this so called 'dual diagnoses' creates a serious challenge in terms of establishing an accurate diagnosis and providing appropriate treatment interventions. The inter-relationship between these disorders appears to be mutually detrimental. The course, manifestation, and treatment of each condition are significantly compounded by the presence of the other condition. Substance abuse and alcoholism appear to significantly complicate the course and prognosis of bipolar disorder resulting in increased suffering, disability, and costs. On the other hand, bipolar disorder may be a risk factor for developing PSUDs. Although, there are a number of hypotheses explaining the pathophysiological mechanism involved in such comorbidities, our understanding of the exact nature of such neurobiological mechanisms is still limited. While the antikindling agents and targeted psychotherapeutic techniques may be useful intervention strategies, there is still a significant lack of empirically based treatment options for these patients.

Genetics of alcohol withdrawal

Alcohol withdrawal is a clinically and etiologically heterogeneous syndrome caused by a complex interaction of environmental (e.g., amount of ethanol) and genetic factors. Multiple genes are considered to be involved in various components of the syndrome, each of them contributing only modestly to withdrawal vulnerability. Association studies using candidate genes of the dopamine, serotonin, gabaergic and opioidergic systems are reviewed and methodological limitations are discussed.

Alcohol and the brain. Pharmacological insights for psychiatrists

BACKGROUND

Alcohol misuse, as well as being a major form of psychiatric morbidity, is also commonly associated with other psychiatric disorders. A greater understanding of the brain mechanisms underlying the adverse effects of alcohol is now possible, thanks to significant research advances made over the past decade.

AIMS

To elucidate for psychiatrists the growing knowledge of the importance of specific neurotransmitter interactions in the effects of alcohol.

METHOD

A survey of the literature, extracting current knowledge of interest to psychiatrists.

RESULTS

There is good evidence that the acute effects of alcohol are mediated through interactions with amino acid neurotransmitters plus parallel changes in amines such as noradrenaline, dopamine and serotonin. Neuroadaptive responses at amino acid receptors probably underlie significant components of the withdrawal syndrome and probably also contribute to neuronal death found in chronic alcoholism.

CONCLUSIONS

An understanding of the pharmacology of alcohol use may lead to greater ability to treat psychiatric consequences of alcoholism, and may also prevent some of the secondary psychiatric comorbidity and later brain damage.

Immunocytochemical analysis of glutamate and GABA in selectively bred mice

Withdrawal Seizure Prone (WSP) and Withdrawal Seizure Resistant (WSR) mice have been selectively bred for differential ethanol withdrawal handling-induced convulsions (HICs). In addition, it has been observed that WSP mice exhibit drug-naive HICs. This latter finding suggests that WSP and WSR mice differ in their susceptibility to HICs. Alterations in the glutamate and gamma-aminobutyric acid (GABA) systems have been implicated in convulsive activity and have been proposed to underlie the manifestation of ethanol withdrawal symptoms. It is therefore possible that WSP and WSR mice are genetically different with respect to their glutamatergic and/or GABAergic systems. To test this hypothesis, we have analyzed WSP and WSR mice that are both drug- and HIC-naive for differences in the density of nerve terminal glutamate and GABA immunoreactivity within the CA1 subfield of the hippocampus (CA1) and layer II of the somatosensory cortex (SSC). The major finding of this study is that drug- and HIC-naive WSP mice exhibit a significantly greater density of presynaptic glutamate immunoreactivity associated with asymmetric synapses within the CA1, but not the SSC, when compared to WSR mice. The density of GABA immunoreactivity within nerve terminals associated with symmetric synapses does not differ between the selected lines in either brain region. Since prior drug exposure and HICs cannot account for the observed differences in these naive mice, the results strongly suggest that the density of nerve terminal glutamate immunoreactivity within the CA1 is a reflection of inherent genetic differences between WSP and WSR mice. Furthermore, an elevated density of presynaptic glutamate immunoreactivity may be an underlying neurochemical correlate to increased susceptibility to drug-naive and ethanol withdrawal convulsions.

Taurine increases in the nucleus accumbens microdialysate after acute ethanol administration to naive and chronically alcoholised rats

The extracellular changes of amino acids (glutamate, taurine and GABA) in the nucleus accumbens of freely moving rats were estimated using the microdialysis technique following acute and chronic ethanol injections (1, 2, and 3 g/kg body weight). Compared to baseline values, taurine increased by 154% +/- 73%, 142% +/- 40% and 162% +/- 75% 20 min after the acute injection of respectively, 1, 2, and 3 g/kg body weight ethanol, while 40 min after ethanol injection, taurine had increased by 124% +/- 36%, 146% +/- 54% and 168% +/- 98%. No changes in either glutamate or GABA were detected at any time points assayed. In the rats which had received chronic ethanol administration prior to a further acute ethanol injection (1, 2, and 3 g/kg body weight), taurine increased by 138% +/- 73%. 144% +/- 39% and 180% +/- 85% 20 min after the ethanol injection at 40 min post ethanol injection taurine had increased by 134% +/- 44%, 160% +/- 56% and 158% +/- 45%, compared to the basal baseline value. No significant changes were observed in either glutamate or GABA microdialysate content in these chronic studies. The biological role played by taurine after acute ethanol injection in the nucleus accumbens remains unclear but may be associated with a yet, undefined mechanism, in reducing the cytotoxicity of ethanol.

Glutamate and benzodiazepine receptor autoradiography in rat brain after repetition of alcohol dependence

During repeated alcohol withdrawal, convulsive withdrawal behavior has been shown to be increased in a kindling-like manner in both clinical and experimental studies. In the present experiment, quantitative autoradiography was used to investigate binding of tritiated ligands to glutamate receptor subtypes and the benzodiazepine/GABA (BZ/GABA) receptor complex in rats exposed to 14 episodes of alcohol withdrawal. Seizures were detected in 25% of the animals during withdrawal episode 10-13. Repeated alcohol withdrawal resulted in a decrease in the number of [3H]-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid ([3H]-AMPA) binding sites in striatum and sub-regions of the entorhinal cortex, the cerebellum and the hippocampus, while the [3H]-flunitrazepam binding was down-regulated in the frontal cortex. There was no differences between the controls and the multiple withdrawal animals regarding the [3H]-dizocilpine ([3H]-MK801) binding and the [3H]-kainic acid binding. However, within the latter group, those animals in which withdrawal seizures were observed had increased [3H]-MK801 binding sites in focal regions of entorhinal cortex and hippocampus, compared to those in which seizures were not observed. The decreased AMPA binding suggested impaired glutamate neurotransmission. As such, this receptor probably did not contribute to alcohol withdrawal kindling, but rather was involved in seizure protective mechanisms during this process.

Effects of ethanol administration on brain neurotensin-like immunoreactivity in rats

The effects of acute and chronic ethanol administration on neurotensin-like immunoreactivity (NTLI) were investigated in discrete regions of the rat brain. Rats were administered a single dose (5 g/kg) of ethanol or rendered ethanol-dependent by repeated forced drinking of a 20% ethanol solution (6-15 g/kg) for 4 days and tested while still intoxicated or at 12-19 h (W-1) or 7 days (W-2) after ethanol withdrawal. Increases in NTLI were seen in the caudate-putamen in the toxic, W-1 and W-2 groups and decreases were observed in the midbrain in the toxic and W-1 groups. It was assumed that ethanol produced the changes of NTLI in the caudate-putamen and midbrain through its actions upon the dopaminergic system.

Striatal D2 dopamine receptor binding characteristics in vivo in patients with alcohol dependence

Striatal D2 dopamine receptor characteristics of nine male patients with alcohol dependence abstinent for 1-68 weeks and eight healthy male volunteers were studied in vivo with positron emission tomography. The selective D2 receptor ligand [11C]raclopride and equilibrium model was used for D2 receptor density (Bmax) and affinity (Kd) measurements. A trend for a decreased striatal D2 receptor density and for reduced D2 receptor affinity was observed in patients with alcohol dependence. These parameters were not statistically significantly different between alcoholics and controls, but the ratio between D2 receptor density and affinity (Bmax/Kd or the striatum/cerebellum ratio from the high specific activity scan) was highly significantly lower in alcoholics than that of controls. In conclusion, the low D2 dopamine receptor Bmax/Kd ratio (striatum/cerebellum ratio) indicates that specific aspects of striatal [11C]raclopride binding in vivo are deviant in alcoholics compared to controls. The result is compatible with a reduced avidity of striatal dopamine D2 receptors in alcoholics, which is in line with the idea that D2 dopaminergic mechanisms are involved in the biology of alcohol dependence in man.

Effects of dizocilpine in withdrawal seizure-prone (WSP) and withdrawal seizure-resistant (WSR) mice

Mice selectively bred to be Withdrawal Seizure-Prone (WSP) or Seizure-Resistant (WSR) after chronic ethanol administration have been reported to be differentially sensitive to the anticonvulsant and proconvulsant effects on alcohol withdrawal of drugs interacting with glutamate receptors. Several behavioral effects of the noncompetitive glutamate receptor antagonist, dizocilpine, were determined in WSP and WSR mice to see whether their differential sensitivity generalized to effects unrelated to seizures, and to see whether it was only apparent during ethanol withdrawal. Dizocilpine potentiated the loss of righting reflex induced by ethanol, and dose-dependently stimulated habituated and nonhabituated open field activity. WSP and WSR mice were equally sensitive to these effects of dizocilpine. Pretreatment with dizocilpine increased the transcorneal amperage necessary to produce maximal electroshock seizures: WSR mice were more sensitive than WSP to this effect. Ethanol withdrawal (i.e., testing 6 h after a 24-h exposure to ethanol vapor) and dizocilpine had several effects on mice tested in the hole-in-wall apparatus. Several differences between WSP and WSR mice were also found, but in no case did dizocilpine differentially affect ethanol-withdrawing WSP and WSR mice. Across these experiments, differences between WSP and WSR mice in response to dizocilpine were rather specific. For some responses, WSP and WSR mice were equally sensitive, but only in the seizure-related measure assessed were naive WSR mice more sensitive than WSP.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of acute alcohol withdrawal on sensitivity to pro- and anticonvulsant treatments in WSP mice

Through the genetic technique of selective breeding, a mouse line [Withdrawal Seizure Prone (WSP)] has been developed that expresses severe handling-induced convulsions (HIC) after cessation of chronic ethanol exposure. These mice also display rebound elevations in HIC after a single ethanol injection. In the current studies, we tested WSP mice in several paradigms. WSP mice were found to be marginally sensitive to the effects of acute doses of dizocilpine to reduce HIC. However, when tested during acute withdrawal from a single ethanol injection, WSP were more sensitive to this compound. Although N-methyl-D-aspartate significantly elevated HIC in naive WSP mice, it was more effective at low doses when given during acute withdrawal. Withdrawing mice were slightly more sensitive than naive mice to kainic acid. Pentylenetetrazole elevated HIC in naive and withdrawing mice; it was marginally more effective in naive mice. Diazepam inhibited HIC in both naive and withdrawing mice, and was slightly more effective during acute withdrawal. This pattern of results suggests that acute alcohol withdrawal is accompanied by altered sensitivity to convulsants and anticonvulsants. These changes include enhanced sensitivity in at least two excitatory amino acid-gated ion channel binding sites.