References of "Quertemont, Etienne"
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See detailConditioned stimulus preference after acetaldehyde but not ethanol injections
Quertemont, Etienne ULg; De Witte, Philippe

in Pharmacology, Biochemistry & Behavior (2001), 68

Acetaldehyde, the first ethanol metabolite, has been suggested to mediate some of the behavioral effects of ethanol and particularly its reinforcing properties, although this later hypothesis remains ... [more ▼]

Acetaldehyde, the first ethanol metabolite, has been suggested to mediate some of the behavioral effects of ethanol and particularly its reinforcing properties, although this later hypothesis remains extremely controversial. While several studies demonstrated the reinforcing effects of brain acetaldehyde, blood acetaldehyde accumulation is believed to be primarily aversive. In the present study, a conditioned reinforcement procedure has been used to investigate the reinforcing and/or aversive effects of intraperitoneal injections of both acetaldehyde and ethanol in Wistar rats. An olfactory stimulus was paired with daily injections of either ethanol (0, 0.25, 0.5, 1 and 2 g/kg) or acetaldehyde (0, 10, 20, 100 and 150 mg/kg). After eight conditioning sessions, all rats were tested for their stimulus preference or aversion. The results show that conditioning with small, 0.25 and 0.5 g/kg, ethanol doses induced neither preference nor aversion for the olfactory cue. In contrast, higher ethanol doses (1.0 and 2.0 g/kg) resulted in significant stimulus aversions. Acetaldehyde conditioning led to a biphasic stimulus preference, with a maximal preference around 20 mg/kg acetaldehyde. No evidence of aversive effects was found with increasing doses of acetaldehyde, even with concentrations close to the lethal limit. The present study clearly shows that systemic acetaldehyde injections induced significant stimulus preferences. This suggests that acetaldehyde may be, at least in part, responsible for the reinforcing effects of alcohol intake. [less ▲]

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See detailEthanol-induced taurine release in rats genetically selected for ethanol preference and sensitivity
Quertemont, Etienne ULg; Colombo, Giancarlo; De Witte, Philippe

in Alcohol & Alcoholism (2001), 36

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See detailImplications of acetaldehyde in ethanol reinforcing and discriminative effects
Quertemont, Etienne ULg; Rios, Ananda; Macias, Enrique et al

in Alcohol & Alcoholism (2001), 36

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See detailEthanol-induced brain extracellular taurine release: an osmoregulatory mechanism?
Quertemont, Etienne ULg; Devitgh, Audrey; De witte, Philippe

in Alcohol & Alcoholism (2001), 36

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See detailNeurochemical and behavioral effects of ethnaol-conditioned stimuli: implication for alcohol consumption
Quertemont, Etienne ULg; De Witte, Philippe

in Cahiers de l'I.R.E.B. (2001), 15

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See detailEffets comportementaux et neurochimiques de stimuli associés à l’administration d'éthanol: implications pour les comportements d'alcoolisation
Quertemont, Etienne ULg; De Witte, Philippe

in Cahiers de l'I.R.E.B. (2001), 15

Les drogues, y compris l’alcool, peuvent servir de stimuli inconditionnels dans des situations d’apprentissage par conditionnement. Les stimuli environnementaux qui accompagnent systématiquement ... [more ▼]

Les drogues, y compris l’alcool, peuvent servir de stimuli inconditionnels dans des situations d’apprentissage par conditionnement. Les stimuli environnementaux qui accompagnent systématiquement l’administration d’alcool peuvent ainsi acquérir le statut de stimuli conditionnés capables d’induire à eux seuls des réactions physiologiques conditionnées. Deux types de réactions conditionnées avec l’alcool ont été observées. D’une part, les stimuli associés à l’administration d’alcool peuvent induire des effets similaires à ceux de l’éthanol. D’autre part, ces stimuli conditionnés à l’éthanol peuvent aussi engendrer des réponses conditionnées opposées aux effets de l’éthanol. Ces deux types de réponses conditionnées semblent jouer un rôle dans les différentes étapes de l’alcoolisation. Leur implication dans la tolérance envers l’éthanol est largement illustrée par le phénomène de tolérance dépendante de l’environnement. Plusieurs études expérimentales et observations cliniques suggèrent aussi que les processus de conditionnement pourraient être impliqués dans la consommation d’alcool et particulièrement dans son abus. Toutefois, les bases neurochimiques de ces réponses conditionnées à l’éthanol sont encore largement méconnues. De récentes études utilisant la technique de microdialyse intracérébrale ont pourtant montré le rôle de divers neurotransmetteurs et neuromodulateurs. D’une part, les réponses conditionnées similaires à l’éthanol sont accompagnées d’une libération de dopamine dans le noyau accumbens. D’autre part, la libération conditionnée de glutamate et de taurine semble être impliquée dans les réponses conditionnées opposées aux effets de l’éthanol. [less ▲]

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See detailTaurine and ethanol preference : a microdialysis study using Sardinian alcohol-preferring and non-preferring rats
Quertemont, Etienne ULg; Lallemand, Frédéric; Colombo, Giancarlo et al

in European Neuropsychopharmacology (2000), 10

Recent intracerebral microdialysis studies of different rat brain regions have shown that an acute ethanol injection induced a rapid dose-dependent increase in taurine microdialysate content during the ... [more ▼]

Recent intracerebral microdialysis studies of different rat brain regions have shown that an acute ethanol injection induced a rapid dose-dependent increase in taurine microdialysate content during the first 60-min period. In taurine-supplemented rats, a reduced aversion for high ethanol doses was observed in a place conditioning paradigm, suggesting that taurine may be implicated in the regulation of some adverse effects of ethanol. The present study compares the effects of acute ethanol injections (1.0 and 2.0 g/ kg, i.p.) on taurine nucleus accumbens microdialysate content in Sardinian ethanol-preferring (sP) and Sardinian ethanol-non preferring (sNP) rats. While neither saline nor 1.0 g/kg ethanol injections had significant effect on taurine microdialysate concentration, 2.0 g/kg ethanol administration induced a rapid and significant increase in taurine microdialysate content in both sP and sNP rats. However, this ethanol-induced taurine release was significantly reduced in sP rats by comparison to sNP rats. As taurine is suggested to be released by brain cells to modulate different ethanol adverse effects, this lower taurine responsiveness to ethanol in sP rats by comparison to both sNP and Wistar rats may be a relevant indicator of reduced ethanol aversive effects in such animals and therefore be related to their higher alcohol consumption. [less ▲]

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See detailBehavioral and neurochemical effects induced by alcohol-conditioned stimuli
Quertemont, Etienne ULg; De Witte, Philippe

in Cahiers de l'I.R.E.B. (2000), 14

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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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