Abstract
The alcohol-preferring P and alcohol-nonpreferring NP lines of rates have been selectively bred and used to study the behavioral and biochemical correlates of alcohol-seeking behavior. The P rats satisfy all the perceived criteria for an animal model of alcoholism. Specifically, free-fed P rats voluntarily drink alcoholic solutions (10 to 30% v/v) to intoxication; they bar-press to obtain alcohol and self-administer ethanol intragastrically when food and water are available; and they acquire metabolic and neuronal tolerance and develop physical dependence when they drink alcohol chronically in a free-choice situation. The spontaneous motor activity in the P rats, but not in the NP rats, is stimulated acutely by low doses of alcohol. With a single hypnotic dose of ethanol, acute tolerance develops faster and to a greater degree and persists many days longer in the P than in the NP rats. These differences in response to ethanol may explain the disparate alcohol drinking behaviors of the P and NP rats. Biochemically, the P rats exhibit decreased serotonin levels in several brain regions including the nucleus accumbens. Serotonin uptake inhibitors curtail the alcohol drinking of the P rats suggesting a role of serotonin in mediating alcohol preference.
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Lawrence Lumeng
Both authors formerly Public Health Officers, Eastern Sydney Area Public Health Unit Previously general practitioner, Orange NSW, Australia.