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Alcohol and Alcoholism - current issue
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Ethanol Increases GABAergic Transmission and Excitability in Cerebellar Molecular Layer Interneurons from GAD67-GFP Knock-in Mice
AimsThis study assessed the acute effect of ethanol on GABAergic transmission at molecular layer interneurons (MLIs; i.e. basket and stellate cells) in the cerebellar cortex. The actions of ethanol on spontaneous firing of these pacemaker neurons were also measured. MethodsTransgenic mice (glutamic acid-decarboxylase 67-green fluorescent protein knock-in mice) that express green fluorescence protein in GABAergic interneurons were used to aid in the identification of MLIs. Parasagittal cerebellar slices were prepared and whole-cell patch-clamp electrophysiological techniques were used to measure GABAA receptor-mediated spontaneous and miniature inhibitory postsynaptic currents (sIPSCs and mIPSCs). Loose-seal cell-attached recordings were used to measure spontaneous action potential firing. ResultsStellate cells received spontaneous GABAergic input in the form of a mixture of action potential-dependent events (sIPSCs) and quantal events (mIPSCs); ethanol increased sIPSC frequency to a greater extent than mIPSC frequency. Ethanol increased spontaneous action potential firing of MLIs, which could explain the increase in sIPSC frequency in stellate cells. Basket cells received GABAergic input in the form of quantal events only. Ethanol significantly increased the frequency of these events, which may be mediated by a different type of interneuron (perhaps, the Lugaro cell) or Purkinje cell collaterals. ConclusionsEthanol exposure differentially increases GABA release at stellate cell vs. basket cell-to-Purkinje cell synapses. This effect may contribute to the abnormalities in cerebellar function associated with alcohol intoxication.
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Ethanol Consumption Alters the Expression and Reactivity of Adrenomedullin in the Rat Mesenteric Arterial Bed
Aims: Adrenomedullin (AM) is a peptide that displays cardiovascular protective activity. We investigated the effects of chronic ethanol consumption on arterial blood pressure, vascular reactivity to AM and the expression of AM system components in the rat mesenteric arterial bed (MAB). Methods: Male Wistar rats were treated with ethanol (20% vol/vol) for 6 weeks. Systolic, diastolic and mean arterial blood pressure were monitored in conscious rats. Vascular reactivity experiments were performed on isolated rat MAB. Matrix metalloproteinase-2 (MMP-2) levels were determined by gelatin zymography. Nitrite and nitrate generation were measured by chemiluminescence. Protein and mRNA levels of pre-pro-AM, CRLR (calcitonin receptor-like receptor) and RAMP1, 2 and 3 (receptor activity-modifying proteins) were assessed by western blot and quantitative real-time polymerase chain reaction, respectively. Results: Ethanol consumption induced hypertension and decreased the relaxation induced by AM and acetylcholine in endothelium-intact rat MAB. Phenylephrine-induced contraction was increased in endothelium-intact MAB from ethanol-treated rats. Ethanol consumption did not alter basal levels of nitrate and nitrite, nor did it affect the expression of MMP-2 or the net MMP activity in the rat MAB. Ethanol consumption increased mRNA levels of pre-pro-AM and protein levels of AM in the rat MAB. Finally, no differences in protein levels or mRNA of CRLR and RAMP1, 2 and 3 were observed after treatment with ethanol. Conclusion: Our study demonstrates that ethanol consumption increases blood pressure and the expression of AM in the vasculature and reduces the relaxation induced by this peptide in the rat MAB.
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Personality Traits and Coping Compensate for Disadvantageous Decision-making in Long-term Alcohol Abstinence
Aims: High relapse rate and extreme difficulty to maintain abstinence are core characteristics of alcohol dependence (AD). Previous studies have demonstrated a persistent decision-making (DM) deficit in AD. We aimed to reveal specific personality features and stress-coping mechanisms presumed to compensate for ineffective DM skills. Methods: Eighty-eight unmedicated patients with AD were enrolled. Intact general cognitive status was assured by IQ above 90. Forty-three patients had an average abstinence period of 12 weeks and were currently in an inpatient treatment program (short-term abstinence group, STA) and 45 patients were abstinent for at least 3 years (long-term abstinence group, LTA). The two groups were assessed using an integrative approach combining domains of DM, temperament and character dimensions and stress-coping measures. Results: Both groups performed at chance level with no linear improvement tendency on the gambling task assessing DM adequacy. The LTA group scored significantly higher on scales of self-directedness and cooperativeness. In contrast, levels of harm avoidance, emotion-oriented coping and perceived stress were significantly higher in the STA group. Conclusion: Our findings provide new evidence for a persistent DM deficit with no learning effect in AD. Despite the deficit, alcohol-dependent patients can achieve LTA. STA patients perceive higher levels of stress and use non-adaptive coping strategies. We propose that the more adaptive personality profile of LTA patients contributes to the compensation of the trait-like DM deficit in alcoholism. These compensatory features represent promising new targets for preventive measures and therapeutic interventions in AD.
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Brief Alcohol Intervention by Newly Trained Workers Versus Leaflets: Comparison of Effect in Older Heavy Drinkers Identified in a Population Health Examination Survey: A Randomized Controlled Trial
Aims: To test if a brief motivational intervention (BMI) in a non-treatment seeking population of heavy drinkers results in a reduced alcohol intake. Methods: Screening of 12,364 participants in a Danish health examination survey led to 1026 heavy drinkers of whom 772 were included and randomized to a BMI group (n = 391) or a control group (n = 381) receiving two leaflets about alcohol. Follow-up took place after 6 and 12 months including 670 and 616 participants respectively. The outcome measure was self-reported weekly alcohol consumption. Data were analysed according to the intention-to-treat principle. We used the Motivational Interviewing Treatment Integrity 3.0 code (MITI) as a quality control of the interventions delivered. Results: The intervention effect of the BMI was –1.0 drinks/week, but the effect was not significant. The MITI analysis showed that the quality of the BMI delivered was sub-optimal, as only one of four aspects was above the recommended level for beginning proficiency. Conclusion: We found no effect of a BMI in reducing alcohol consumption. The generalizability of the study is questionable, as individuals with the lowest level of education, low income and unmarried individuals are under-represented.
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Atypical Antipsychotic Drugs and Ethanol Withdrawal Syndrome: A Review
Aims: Alcoholism and psychosis are known to have common neurochemical substrates. The aim of this review is to assess the reports involved in the effects of some atypical antipsychotic agents on the signs of ethanol withdrawal syndrome (EWS) in rats. Thus, both effectiveness of these drugs in ethanol withdrawal and the association between the drug effects and the signs have been investigated here on the same animal model. Methods: Adult Wistar rats were used as subjects. Ethanol was given to rats by modified liquid diet technique for inducing ethanol dependence. Clozapine, olanzapine, risperidone, quetiapine and ziprasidone were the drugs tested. Effects of these drugs on the signs of ethanol withdrawal such as locomotor hyperactivity, stereotyped behavior, tremor, wet dog shakes, tail-stiffness, abnormal posture and gait, agitation and audiogenic seizures were evaluated for the first 6 h of ethanol withdrawal. Results: Although some beneficial effects of all the drugs on ethanol withdrawal signs were observed, olanzapine precipitated abnormal posture and gait in the animals. Effectiveness rank of the used atypical antipsychotics was as follows: risperidone = quetiapine > ziprasidone > klozapine > olanzapine. Conclusion: Our results suggest that risperidone and quetiapine seem to be potent and pharmacologically more active agents on EWS in rats. Thus, these drugs may be beneficial in treatment of EWS in patients with alcoholism. Ziprasidone and clozapine also seem to be useful drugs in treatment of ethanol withdrawal.
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