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See detailEthanol induces taurine release in the amygdala: an in vivo microdialysis study
Quertemont, Etienne ULg; Dahchour, Abdelkhader; Ward, Roberta J. et al

in Addiction Biology (1999), 4

The effect of acute IP ethanol injections on the extracellular aspartate, glutamate, taurine and GABA content of the basolateral amygdala microdialysate was investigated in relationship with the total ... [more ▼]

The effect of acute IP ethanol injections on the extracellular aspartate, glutamate, taurine and GABA content of the basolateral amygdala microdialysate was investigated in relationship with the total brain ethanol content. Each acute intraperitoneal injection of ethanol, 0.5, 1.0, 2.0 and 3.0 g/kg body weight, induced an immediate increase in the microdialysate taurine content; both 0.5 and 1.0 g/kg ethanol evoked an increase during the first 20 minutes following injection which returned to baseline value by 40 minutes despite the fact that ethanol was detectable in the brain until 60 or 120 minutes respectively; after either 2.0 or 3.0 g/kg ethanol there was an increase in taurine content of gradual intensity which gradually declined to reach baseline values by 100 minutes. In contrast, the ethanol concentration for 2.0 g/kg remained elevated at the end of the 120 minutes approximately 25 mg ethanol / mg protein. The stimulated release of taurine within the amygdala could participate in the regulation of the ethanol-induced changes in osmolarity, since taurine is postulated to act as an osmoregulator in the brain. Taurine could also mediate or interact with the ethanol-induced CNS effects, as it exerts a modulatory action on cell excitability and neurotransmitter processes. [less ▲]

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See detailBases neurobiologiques des comportements d’alcoolisation: implication des acides aminés neuro-excitateurs et neuro-inhibiteurs
Quertemont, Etienne ULg

Doctoral thesis (1999)

Les théories traditionnelles qui essaient d’expliquer le phénomène d’addiction rencontrent généralement de grandes difficultés à rendre compte de deux particularités importantes de cet état de ... [more ▼]

Les théories traditionnelles qui essaient d’expliquer le phénomène d’addiction rencontrent généralement de grandes difficultés à rendre compte de deux particularités importantes de cet état de pharmacodépendance: le caractère compulsif de la consommation de drogue et la très grande fréquence des rechutes parfois très longtemps après le sevrage. Les théories de l’apprentissage par conditionnement apportent une solution originale à ces questions non résolues. En effet, de nombreuses expériences animales ont démontré que des stimuli environnementaux associés de manière répétée à l’administration de ces drogues peuvent acquérir le statut de stimuli conditionnés capables d’induire à eux seuls certains effets physiologiques et comportementaux spécifiques. On a de plus suggéré que ces réponses conditionnées sont responsables du déclenchement des comportements compulsifs de recherche de drogue et participent dès lors aux rechutes dans sa consommation incontrôlée. Parmi les drogues addictives, l’alcool est probablement la substance la plus difficile à étudier. En effet, sa simplicité moléculaire lui permet paradoxalement d’affecter tous les systèmes de neurotransmission cérébrale. Il est donc difficile d’identifier clairement les bases neurochimiques des différents effets psychotropes de l’alcool. D’autre part, la littérature scientifique confirme également le rôle des apprentissages par conditionnement dans le maintien de la consommation d’alcool et dans l’alcoolodépendance. Bien que l’importance des réponses conditionnées à l’éthanol est maintenant reconnue, les bases neurochimiques de ces effets conditionnés sont encore méconnues. Le présent travail est donc destiné à faire le point sur les connaissances actuelles des bases neurochimiques et comportementales de la consommation d’alcool et de l’addiction alcoolique. Plus particulièrement les neurotransmetteurs acides aminés ont fait l’objet d’investigations expérimentales destinées à élucider leur rôle dans les effets conditionnés à l’éthanol. [less ▲]

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See detailEthanol neurotoxicity: from basic science to clinical reality
De Witte, Philippe; Ward, Roberta; Dahchour, Abdelkhader et al

in Alcohol & Alcoholism (1999), 34

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See detailChanges in the amygdala amino acid microdialysate after conditioning with a cue associated with ethanol
Quertemont, Etienne ULg; de Neuville, Jessica; De Witte, Philippe

in Alcohol & Alcoholism (1999), 34

The excitatory amino acid neurotransmission within the amygdala has been implicated in learning associations between external stimuli and intrinsic reward values such that it may play a key role in ... [more ▼]

The excitatory amino acid neurotransmission within the amygdala has been implicated in learning associations between external stimuli and intrinsic reward values such that it may play a key role in conditioned drug effects. In the present studies, the responses of the excitatory amino acids, aspartate and glutamate together with the neuromodulatory sulphonated amino acid taurine, within the basolateral amygdala, to an odor cue repeatedly associated with acute ethanol injections (2g/kg, IP) have been investigated by a microdialysis technique combined with HPLC-EC analysis. After presentation of the ethanol-conditioned stimulus, a single IP saline injection induced an immediate and significant increase in the taurine microdialysate content which could be related to the neuromodulatory action of taurine. Furthermore, when the conditioned stimulus was combined with the ethanol injection (2g/kg, IP), significant increases in both taurine and glutamate microdialysate content were observed and indicated a learned compensatory response to counteract the acute effects of ethanol. These results demonstrate that changes in amygdala extracellular glutamate and taurine concentrations can be conditioned to ethanol-associated stimuli and are therefore probably implicated in the phenomenon of environmental-dependent tolerance to ethanol. [less ▲]

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See detailAlcohol-non-preferring Sardinian rats exhibit a higher ethanol-induced taurine increase compared to alcohol-preferring Sardinian rats: a microdialysis study
Quertemont, Etienne ULg; Lallemand, Frédéric; Colombo, Giancarlo et al

in Alcohol & Alcoholism (1999), 34

It is well known that ethanol injections induce increases in the extracellular taurine concentration from various rat brain regions. Furthermore, recent studies have shown that taurine supplementation ... [more ▼]

It is well known that ethanol injections induce increases in the extracellular taurine concentration from various rat brain regions. Furthermore, recent studies have shown that taurine supplementation modulates the ethanol reinforcing effects in a place conditioning experiment. However, it is unknown whether there is a relationship between this taurine increase and the ethanol drinking behaviors. In the present microdialysis experiments, we compared the effects of ethanol injections (1.0 and 2.0 g/kg) on the extracellular taurine concentration from the nucleus accumbens of either Sardinian alcohol-preferring or Sardinian alcohol-non-preferring rats which have been selectively bred for their differential ethanol preference. The results show that acute ethanol produces an immediate increase in the taurine microdialysate content from both rat lines. However, this increase in taurine microdialysate content was more potent in the alcohol-non-preferring rats. Since taurine has been postulated to be released by brain cells to modulate some of the adverse effects of ethanol, the higher increase in taurine microdialysate content in the alcohol-non-preferring rats is probably related to their higher vulnerability to ethanol aversive effects. [less ▲]

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See detailChanges in the amygdala amino acid microdialysate after conditioning with a cue associated with ethanol
Quertemont, Etienne ULg; De Neuville, Jessica; De Witte, Philippe

in Psychopharmacology (1998), 139

Excitatory amino acid neurotransmission within the amygdala has been implicated in learning associations between external stimuli and intrinsic reward values, such that it may play a key role in ... [more ▼]

Excitatory amino acid neurotransmission within the amygdala has been implicated in learning associations between external stimuli and intrinsic reward values, such that it may play a key role in conditioned drug effects. In the present studies, the responses of the excitatory amino acids, aspartate and glutamate, together with the neuromodulatory sulphonated amino acid, taurine, within the basolateral amygdala, to an odor cue repeatedly associated with acute ethanol injections (2 g/kg, IP) have been investigated by a microdialysis technique combined with HPLC-EC analysis. After presentation of the ethanol-conditioned stimulus, a single IP saline injection induced an immediate and significant increase in the taurine microdialysate content which could be related to the neuromodulatory action of taurine. Furthermore, when the conditioned stimulus was combined with the ethanol injection (2 g/kg, IP), significant increases in both taurine and glutamate microdialysate content were observed and indicated a learned compensatory response to counteract the acute effects of ethanol. These results demonstrate that changes in amygdala extracellular glutamate and taurine concentrations can be conditioned to ethanol-associated stimuli and are therefore probably implicated in the phenomenon of environmental-dependent tolerance to ethanol. [less ▲]

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See detailAcetaldehyde but not ethanol induces conditioned stimulus preference
Quertemont, Etienne ULg; De Witte, Philippe

in Alcoholism, Clinical & Experimental Research (1998), 22

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See detailThe role of taurine in ethanol reinforcing effects
Quertemont, Etienne ULg; de Bethune, Coraline; De Witte, Philippe

in Alcoholism, Clinical & Experimental Research (1998), 22

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See detailNeurotoxic effects of acetaldehyde
Ward, Roberta J.; Lallemand, Frédéric; Dahchour, Abdelkhader et al

in Alcoholism, Clinical & Experimental Research (1998), 22

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See detailTaurine - a modulator of ethanol toxicity. From basic concepts to clinical reality
Dahchour, Abdelkhader; Lallemand, Frédéric; Quertemont, Etienne ULg et al

in Alcoholism, Clinical & Experimental Research (1998), 22

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See detailCampral: from basic mechanisms to clinical reality
De Witte, Philippe; Ward, Roberta; Dahchour, Abdelkhader et al

in Drugs in focus: Campral - Acamprosate, focus on advances in alcoholism (1998)

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See detailChanges in excitatory and inhibitory amino acids as a possible target for new treatments of alcoholism
De Witte, Philippe; Ward, Roberta; Dahchour, Abdelkhader et al

in International Journal of Neuropsychopharmacology (1998), 1

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See detailAcamprosate appaers to improve survival in alcohol-dependent rats during multiple successive withdrawals
De Witte, Philippe; Ward, Roberta; Dahchour, Abdelkhader et al

in Campral highlights, focus on advances in alcoholism (1998)

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See detailNeurobiologie Comportementale de l'éthanol et de l'acétaldéhyde
Quertemont, Etienne ULg; De Witte, Philippe

in Alcoologie (1998), 20(4), 391-391

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See detailOral taurine supplementation modulates ethanol-conditioned stimulus preference
Quertemont, Etienne ULg; Goffaux, Valérie; Vlaminck, Anne-Michèle et al

in Alcohol (1998), 16(3), 201-206

The present study investigated the possible modulatory action of oral taurine supplementation on the rewarding and aversive properties of low and high ethanol doses in male Wistar rats. A vinegar odor ... [more ▼]

The present study investigated the possible modulatory action of oral taurine supplementation on the rewarding and aversive properties of low and high ethanol doses in male Wistar rats. A vinegar odor stimulus was daily paired with either ethanol (0.3 or 2.0 g/kg) or saline. In addition, half of the rats were supplemented orally with taurine (0.5 g/kg/day). After eight conditioning sessions, all rats were tested for their vinegar stimulus preference or aversion. In nontaurine-treated rats, 2.0 g/kg ethanol conditioning induced a significant aversion for the vinegar stimulus, while there was no preference after 0.3 g/kg ethanol conditioning. However, in taurine-supplemented rats, the 2.0 g/kg ethanol-induced aversion for the stimulus was decreased significantly, while the rats administered the lower ethanol doses, 0.3 g/kg, in combination with taurine supplementation, demonstrated a significant stimulus preference. Such results suggest that taurine modulates some of the aversive or rewarding effects of ethanol. [less ▲]

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See detailAcetaldehyde-induced changes in the monoamine and amino acid extracellular microdialysate content of the nucleus accumbens
Ward, Roberta J.; Colantuoni, Carlo; Dahchour, Abdelkhader et al

in Neuropharmacology (1997), 36(2), 225-232

The effect of an acute intraperitoneal (i.p.) injection of acetaldehyde, 20 mglkg or 100mg/kg, on the microdialysate content of both amino acids and monoamine was studied in the nucleus accumbens (NA) by ... [more ▼]

The effect of an acute intraperitoneal (i.p.) injection of acetaldehyde, 20 mglkg or 100mg/kg, on the microdialysate content of both amino acids and monoamine was studied in the nucleus accumbens (NA) by a microdialysis technique. Acetaldehyde (ACH) which was detectable at levels of 50-130 µmol/g brain tissue 10 min after injection, evoked a significantd ecrease in the extracellular microdialysis dopamine content, which was sustained for the period of the study, i.e. 120 min. Homovanillicacid, HVA, decreased significantly when the lower dose of ACH was administered while dihydrophenylaceticacid, DOPAC, showed no significant change with either dose of ACH during the period of the study. Serotonin levels decreased significantly after both doses of acetaldehyde, with significant increases of its major metabolite, hydroxyindolacetic acid, 5-HIAA, with the higher acetaldehyde dose. Taurine increased significantly, only during the first twenty minutes, after both doses of acetaldehyde, although neither of the excitatory amino acids assayed, glutamate and aspartate, nor the inhibitoryamino acid, GABA, showed any significant changes. Acetaldehyde clearly evokes significant perturbation in the monoamine content of the NA, such changes being the converse to those reported for monoamine after ethanol administration, which might indicate a negative reinforcement effect. [less ▲]

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See detailTaurine supplementation modifies ethanol reinforcing effects in a place conditioning design
Quertemont, Etienne ULg; Goffaux, Valérie; Wolf, Charlotte et al

in Alcohol & Alcoholism (1997), 32

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See detailRole of associative learning in the development of ethanol tolerance
Quertemont, Etienne ULg; Lebout, Gregory; De Witte, Philippe

in Alcohol & Alcoholism (1997), 32

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See detailRole of associative learning in alcohol tolerance and craving
Quertemont, Etienne ULg; Lebout, Gregory; De Witte, Philippe

in Cleermans, Axel; Kolinsky, Régine; Mousty, Philippe (Eds.) Proceedings of the 50th Anniversary Meeting of the Belgian Psychological Society (1997)

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See detailTaurine increases in the nucleus accumbens microdialysate after acute ethanol administration to naive and chronically alcoholised rats
Dahchour, Abdelkhader; Quertemont, Etienne ULg; De Witte, Philippe

in Brain Research (1996), 735

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 ... [more ▼]

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%, 142% and 162%, 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%, 146% and 168%. 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%, 144% and 180%, 20 min after the ethanol injection, and at 40 min post ethanol injection taurine had increased by 134%, 160% and 158%, 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. [less ▲]

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