Differential change in neuroactive steroid sensitivity during ethanol withdrawal.
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The progesterone metabolite 3alpha-hydroxy-5alpha-pregnan-20-one (3alpha,5alpha-P or allopregnanolone) is a potent positive modulator of gamma-aminobutyric acid(A) (GABA(A)) receptors. Although it is well documented that chronic ethanol (EtOH) administration produces cross-tolerance to the positive modulatory effect of benzodiazepines and GABA at GABA(A) receptors, recent findings suggest that sensitivity to 3alpha,5alpha-P is enhanced during EtOH withdrawal. In addition, EtOH-naive inbred strains of mice, which differ in EtOH withdrawal severity (DBA/2 >> C57BL/6), had marked differences in behavioral sensitivity to 3alpha,5alpha-P. Therefore, the present study was conducted to determine whether C57BL/6 (B6) and DBA/2 (D2) mice would be differentially sensitive to several of the pharmacological effects of 3alpha,5alpha-P during EtOH withdrawal. Male mice were exposed to EtOH vapor or air for 72 h. During withdrawal from EtOH, animals were injected with 3alpha,5alpha-P (0, 3.2, 10, or 17 mg/kg i.p.) and tested for activity and anxiolysis on the elevated plus maze, muscle relaxation, ataxia, and seizure protection following pentylenetetrazol. Sensitivity to the anticonvulsant effect of 3alpha,5alpha-P was enhanced during EtOH withdrawal in B6, but not D2 mice. In contrast, sensitivity to the muscle relaxant effects of 3alpha,5alpha-P was reduced in EtOH-withdrawing B6 and D2 mice, with a suggestion of decreased sensitivity to the anxiolytic effect of 3alpha,5alpha-P during EtOH withdrawal in B6. These results suggest that sensitization to the anticonvulsant effect of 3alpha,5alpha-P during EtOH withdrawal does not generalize across all genotypes nor does it generalize to all of the pharmacological effects of 3alpha,5alpha-P. (+info)
Animal models of alcohol withdrawal.
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One diagnostic criterion of alcohol dependence is the appearance of a withdrawal syndrome when alcohol consumption ceases. Researchers have used various animal models, including isolated brain cells, slices of brain tissue, and intact animals, to study the mechanisms and manifestations of withdrawal. Results from these experimental studies have demonstrated that many consequences of withdrawal found in animals resemble those observed in humans. Such signs and symptoms of alcohol withdrawal include enhanced activity of the autonomic nervous system; body posture and motor abnormalities; hyperexcitability of the central nervous system, including sensory hyperreactivity; convulsions; anxiety; and psychological discomfort. Researchers also have used animal models to study the electrophysiological correlates of withdrawal, as well as neurobiological mechanisms underlying alcohol dependence and withdrawal. (+info)
Emergency airway management in a case of lingual haematoma.
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A previously unreported cause of acute tongue swelling is presented and the airway issues discussed. Cases with different aetiology have been sporadically published however the consequent, and sometimes fatal, airway obstructions have been dealt with somewhat variably. The aetiogy of acute tongue swelling and modern emergency airway algorithms are discussed with reference to the literature. (+info)
Influence of clonazepam and carbamazepine on alcohol withdrawal syndrome, preference and development of tolerance to ethanol in rats.
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The effects of clonazepam (0.3 and 1.0 mg/kg or 0.1 mg/kg, b.i.d., 5 days) and carbamazepine (50 and 100 mg/kg or 12.5 and 50 mg/kg b.i.d., 5 days) on alcohol withdrawal syndrome in rats were investigated. Moreover, the influence of clonazepam (0.3 mg/kg, single dose, or repeated doses for 8 days) and carbamazepine (50 mg/kg, single dose, or repeated doses for 8 days) on the development of tolerance to ethanol was also examined. To study the influence of clonazepam and carbamazepine on preference to ethanol, both drugs were administered for 5 days during the last week of the experiment, (clonazepam at 0.1 mg/kg, b.i.d., i.p. and carbamazepine at 12.5 mg/kg, b.i.d, i.p.). Clonazepam and carbamazepine administered at single doses as well as multiple doses diminished the symptoms of withdrawal syndrome. Clonazepam did not prevent the development of tolerance to sleep-inducing and hypothermal action of ethanol, while carbamazepine prevented the development of tolerance to hypnotic effect of ethanol. Carbamazepine clearly reduced preference to ethanol (significantly vs. the control group and vs. the baseline values). Clonazepam also diminished preference to alcohol, but only in comparison with baseline values. (+info)
No association between metabotropic glutamate receptors 7 and 8 (mGlur7 and mGlur8) gene polymorphisms and withdrawal seizures and delirium tremens in alcohol-dependent individuals.
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- Up-regulation of the glutamatergic neurotransmission from chronic ethanol intoxication may cause a hyperexcitable state during alcohol withdrawal that may lead to seizures and delirium tremens. The aim of our study was to evaluate the association between a history of alcohol withdrawal-induced seizures and delirium tremens and a mGlurR7 (Tyr433Phe); and a mGlurR8 (C2756T) metabotropic glutamate receptor polymorphism in alcoholics compared to controls. A total of 182 patients meeting DSM-IV alcohol dependence criteria and 117 controls, both groups being of German descent, were investigated. mGluR7 and mGluR8 polymorphisms were determined using polymerase chain reaction of lymphocyte DNA. History of alcohol withdrawal-induced delirium tremens and seizures were obtained using the Semi-Structured Assessment of Genetics in Alcoholism (SSAGA). Data were cross-checked with inpatients' clinical files. No significant associations were obtained between both receptor polymorphisms and alcohol withdrawal-induced seizures and delirium tremens. The negative results in this study question the role of these polymorphisms in the pathogenesis of alcohol withdrawal-induced seizures and delirium tremens. (+info)
In silico discovery of gene-coding variants in murine quantitative trait loci using strain-specific genome sequence databases.
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BACKGROUND: The identification of genes underlying complex traits has been aided by quantitative trait locus (QTL) mapping approaches, which in turn have benefited from advances in mammalian genome research. Most recently, whole-genome draft sequences and assemblies have been generated for mouse strains that have been used for a large fraction of QTL mapping studies. Here we show how such strain-specific mouse genome sequence databases can be used as part of a high-throughput pipeline for the in silico discovery of gene-coding variations within murine QTLs. As a test of this approach we focused on two QTLs on mouse chromosomes 1 and 13 that are involved in physical dependence on alcohol. RESULTS: Interstrain alignment of sequences derived from the relevant mouse strain genome sequence databases for 199 QTL-localized genes spanning 210,020 base-pairs of coding sequence identified 21 genes with different coding sequences for the progenitor strains. Several of these genes, including four that exhibit strong phenotypic links to chronic alcohol withdrawal, are promising candidates to underlie these QTLs. CONCLUSIONS: This approach has wide general utility, and should be applicable to any of the several hundred mouse QTLs, encompassing over 60 different complex traits, that have been identified using strains for which relatively complete genome sequences are available. (+info)
Lack of association between hippocampal volume reduction and first-onset alcohol withdrawal seizure. A volumetric MRI study.
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AIMS AND METHODS: Magnetic resonance imaging (MRI) of the hippocampus has been extensively studied in both neurological and psychiatric disorders. Furthermore, hippocampal volume reductions on MRI have been reported in patients with chronic alcoholism. The present volumetric MRI study was undertaken to determine whether an association exists between hippocampal volume reduction and first-onset alcohol withdrawal seizure. Until recently, no data as to whether hippocampal volume reductions in alcoholics might serve as a predictor of withdrawal seizures were available. RESULTS: We found the average hippocampal volumes measured by high resolution MRI to be significantly reduced in 52 alcoholics compared with 30 healthy controls. Besides a decrease of hippocampal volume in patients with chronic alcoholism, we could not find any significant correlation between the occurrence of seizures during alcohol withdrawal and the amount of hippocampal volume reduction in these patients. CONCLUSIONS: Thus, the alcoholism-related atrophy within the hippocampal formation in patients suffering from chronic alcoholism does not seem to be the source of convulsive activity in these patients. Neither does the amount of atrophy allow the occurrence of first-onset withdrawal seizures to be predicted. (+info)
Alcohol withdrawal treatment in intoxicated vs non-intoxicated patients: a controlled open-label study with tiapride/carbamazepine, clomethiazole and diazepam.
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AIMS AND METHODS: Alcohol withdrawal treatment efficacy of tiapride/carbamazepine (A) vs clomethiazole (B) vs diazepam (C) in non-intoxicated patients and vs tiapride/carbamazepine in intoxicated patients (D; breath alcohol concentration > or = 1 g/l) was tested (n = 127) in a controlled randomized open-label study. RESULTS: Efficacy and safety were not different between groups (total group: delirium, 3.9%; seizure, 0.8%), except for a lack of efficacy in 18% of intoxicated tiapride/carbamazepine patients. A change of medication in this group was necessary only when primarily intoxicated patients had reached the non-intoxicated range. CONCLUSIONS: Treatment with tiapride/carbamazepine in alcohol-intoxicated patients proved to be safe. (+info)