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| 2. |
- Fahlke, Claudia, 1964, et al.
(author)
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Audiogenic immobility reaction and open-field behavior in AA and ANA rat lines.
- 1993
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In: Alcohol (Fayetteville, N.Y.). - 0741-8329. ; 10:4, s. 311-5
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Journal article (peer-reviewed)abstract
- Individual predispositions in emotional reactivity have been suggested as factors involved in the development of alcoholism. To approach this problem, we assessed emotional reactivity in alcohol-naive animals from the alcohol-preferring (AA) and alcohol-avoiding (ANA) rat lines of Alko Ltd. AA rats are known to have higher brain levels of 5-hydroxytryptamine (5-HT) than ANA rats. Emotional reactivity was therefore assessed by an audiogenic immobility reaction (freezing), which is specifically sensitive to and shortened by depletion of 5-HT. The results showed that AA rats of both sexes displayed increased immobility reactions compared to the corresponding sex of the ANA rats. During the period of adaptation to the test cage ANA rats of both sexes showed increased locomotor activity compared to the corresponding sex of the AA rats. Levels of plasma corticosterone did not differ between the rat lines, either during resting or stressful conditions. The present results suggest that a passive, inhibited style of defensive behavior is associated with a high alcohol consumption.
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| 3. |
- Fahlke, Claudia, 1964, et al.
(author)
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Effects of ventral striatal 6-OHDA lesions or amphetamine sensitization on ethanol consumption in the rat.
- 1994
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In: Pharmacology, biochemistry, and behavior. - 0091-3057. ; 47:2, s. 345-9
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Journal article (peer-reviewed)abstract
- Female rats with continuous access to water and 6% ethanol were given bilateral ventral striatal 6-OHDA infusions, which induced pronounced striatal depletions of dopamine. The postoperative ethanol consumption of these rats was not significantly affected in comparison to vehicle-infused controls. In a second experiment, female rats received escalating doses of d-amphetamine over a 5-week period (from 1 to 9 mg/kg/injection). Control females were given saline injections. Following a 3-month drug-free interval, the females were given access to ethanol, the concentration of which was gradually increased from 2% to 12% with weekly intervals. Amphetamine-sensitized rats consumed significantly more alcohol than the saline-treated controls. Taken together, these results suggest that striatal dopaminergic mechanisms, while not necessary for basal ethanol drinking, can facilitate alcohol drinking.
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| 4. |
- Fahlke, Claudia, 1964, et al.
(author)
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Involvement of corticosterone in the modulation of ethanol consumption in the rat.
- 1994
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In: Alcohol (Fayetteville, N.Y.). - 0741-8329. ; 11:3, s. 195-202
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Journal article (peer-reviewed)abstract
- Several studies report that rats exposed to stressful conditions may increase their ethanol consumption. Stress is accompanied by a rise in the secretion of adrenocortical hormones, and the possibility that these hormones exert an influence on ethanol consumption should be considered. The present investigation addressed this issue by studying the effect of adrenalectomy (ADX) and subsequent corticosterone (CORT) or aldosterone (ALDO) treatment on ethanol intake. The results showed that ADX rats decreased their ethanol intake compared to the sham-operated controls and that treatment with CORT restored the intake of ethanol to the preoperative level. In contrast, treatment with ALDO (0.25 or 0.75 mg/kg) had no effect on ethanol intake. Biochemical analyses showed increases in monoamine turnover in the brain stem and limbic forebrain after ADX. The reduction of ethanol consumption caused by ADX may thus be specifically attributed to the loss of one of the adrenal hormones, CORT. The results indicate that CORT may be a factor of importance in the modulation of alcohol consumption.
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| 5. |
- Fahlke, Claudia, 1964, et al.
(author)
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Metyrapone-induced suppression of corticosterone synthesis reduces ethanol consumption in high-preferring rats.
- 1994
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In: Pharmacology, biochemistry, and behavior. - 0091-3057. ; 48:4, s. 977-81
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Journal article (peer-reviewed)abstract
- The fluid intake of male Wistar rats with simultaneous access to water and 6% ethanol was determined between 0900 and 1500 h. In high-preferring males (normally covering > 60% of their daily fluid consumption in the form of ethanol), two injections with the corticosterone synthesis inhibitor metyrapone (50 mg/kg) at 0900 h and 1200 h for 4 consecutive days significantly reduced ethanol preference such that they preferred water over alcohol. Treatment with corticosterone (0.6 mg/kg) 2 h before each metyrapone injection partially cancelled this effect of the synthesis inhibitor. By contrast, there was no significant effect of metyrapone treatment on the drinking of ethanol in low-preferring rats (normally covering < 30% of their daily fluid consumption in the form of ethanol). These results suggest that the adrenal secretion of corticosterone directly or indirectly modulates the intake of alcohol in high-preferring rats.
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| 6. |
- Fahlke, Claudia, 1964, et al.
(author)
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Taste reactivity to ethanol in rats: Influence of adrenalectomy or ipsapirone
- 1994
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In: Alcohol. - : Elsevier BV. - 0741-8329. ; 11, s. 289-294
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Journal article (peer-reviewed)abstract
- The affective mimetic responses of male Wistar rats with prior access to 6% ethanol in their home cages were observed during intraoral infusions of an equivalent alcohol solution. Ethanol preference in the home cage appeared unrelated to measures of aversion and ingestion in the taste reactivity tests in normal rats. Adrenalectomy, which significantly reduced home cage ethanol preference, failed to influence the taste reactions elicited by ethanol or water. On the other hand, treatment of intact rats with the 5-HT1Areceptor agonist ipsapirone (2.5 mg/kg), a drug that also decreases ethanol drinking in two-bottle intake tests, did increase the duration of aversive groomings, whereas measures of ingestion remained unaffected. These results suggest that ipsapirone, but not adrenalectomy, may alter the palatibility of ethanol; this perceptual change may partly underlie the ability of ipsapirone to reduce home cage alcohol drinking in the rat. © 1994.
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| 8. |
- Svensson, Lennart, et al.
(author)
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Involvement of the serotonergic system in ethanol intake in the rat
- 1993
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In: Alcohol. - 0741-8329. ; 10, s. 219-224
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Journal article (peer-reviewed)abstract
- A two-bottle, free-choice paradigm was used to investigate the influence of the serotonergic (5-HT) system on ethanol intake in genetically heterogeneous Wistar rats. Systemic administration of the 5-HT1Aagonist ipsapirone (1.25-5.0 mg/kg) caused a dose-dependent decrease in ethanol preference and intake, while the 5-HT2antagonist ritanserin (1.25-5.0 mg/kg) and the 5-HT3antagonists ondansetron (0.01-1.0 mg/kg) and granisetron (0.5-1.0 mg/kg) failed to alter ethanol consumption. The effect of ipsapirone treatment on ethanol intake was more pronounced in high-preferring animals than in low-preferring. A closer look at the microstructure of the rat's drinking behaviour by means of a microcomputer-controlled data acquisition system showed that ipsapirone treatment caused a significant decrease in the number of licks recorded at the ethanol-containing bottle and a decrease in the time spent at this bottle. Furthermore, ipsapirone treatment caused a significant increase in the number of breaks in licking behaviour recorded at this bottle. The drinking behaviour at the water-containing bottle was not affected by the ipsapirone treatment. Neither was the rat's eating behaviour altered by this treatment. These findings support the hypothesis that the 5-HT system is involved in the regulation of ethanol intake, with special emphasis on the involvement of the 5-HT1Areceptor subtype, and may indicate that central reward-mediating mechanisms are influenced. © 1993.
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