Tolerance and sensitization to the hypnotic effects of alcohol induced by chronic voluntary alcohol intake in rats

Sònia Darbra, Gemma Prat, Marc Pallarés, Nuria Ferré

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17 Citations (Scopus)


The effect of a chronic alcohol exposure on the development of tolerance to the depressive effects of alcohol were examined in male Wistar rats that voluntary self-administered alcohol. A free-choice drinking procedure based on the limited access paradigm and the addition of glucose that implies an early availability of the alcoholic solution was used (Alcoholism Primary Praecox procedure). Alcohol induced sleep time (3.5 g alcohol per kg i.p.) was measured at 90 days (after 2 months of alcohol consumption) or at 60 + 90 days old (1 or 2 months of alcohol consumption). The psychomotor performance was also evaluated by means of an 80° inclined screen test. Subjects that had been tested for the hypnotic effects at both 60 and 90 days showed a higher intake of alcoholic solution than the animals only tested at 90 days. The same consumption increase was observed in the glucose group. No significant differences between groups were observed in the inclined screen test. Tolerance to the hypnotic effects of alcohol was observed at 90 days. On the other hand, no significant differences between alcohol and control groups (glucose or water) were observed in the sleep time at 60 days. In the alcohol-drinking rats tested for two trials (60 and 90 days), sensitization instead of tolerance to the second hypnotic alcohol injection was seen. Tolerance to the hypnotic effects of alcohol observed after chronic voluntary alcohol consumption may provide animal models of alcoholism based on limited access to sweetened alcoholic solutions with construct validity.
Original languageEnglish
Pages (from-to)79-83
JournalJournal of Psychopharmacology
Issue number1
Publication statusPublished - 1 Jan 2002


  • Alcohol depressant effects
  • Alcohol induced sleep-time
  • APP procedure
  • Oral self-administration
  • Sensitization
  • Tolerance
  • Wistar rats


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