Specific decreases in ethanol- but not water-reinforced responding produced by the 5-HT3 antagonist ICS 205-930.
The serotonin 5-HT3 antagonist ICS 205-930 has been shown to block the discriminative stimulus properties of ethanol and decrease voluntary intake, suggesting a possible role for 5-HT3 systems in the reinforcing effects of ethanol. ICS 205-930 (0.56, 1.0, 3.0, 10.0, and 17.0 mg/kg i.p.) was examined on ethanol and water self-administration in an operant paradigm. Following a sucrose-fading procedure, two groups of nondeprived rats responded on either a concurrent fixed ratio 4 schedule for ethanol (10% v/v) and water (CONC FR4 FR4), or a single FR4 schedule for ethanol (10% v/v). ICS 205-930 dose-dependently decreased ethanol-reinforced responding in the concurrent condition without decreasing water-reinforced responding, suggesting a specific effect on ethanol. Ethanol-reinforced responding was also dose-dependently decreased in the single FR4 condition, but the dose effect curve was shifted to the left. These data support the conclusions that 5-HT3 systems may play a specific role in ethanol self-administration that is independent of general appetitive and motor processes, and that 5-HT3 antagonists may have therapeutic efficacy in the treatment of alcohol abuse when multiple reinforcers are available.
Alcohol and Drug Abuse Institute, University of Washington, Seattle 98195.
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Hodge
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Samson
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Lewis
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Erickson
D000428:Alcohol Drinking; D000818:Animals; D003216:Conditioning, Operant / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D000431:Ethanol / Q000008:administration & dosage / Q000494:pharmacology*; D007211:Indoles / Q000494:pharmacology*; D008297:Male; D051381:Rats; D012054:Reinforcement, Psychology; D012646:Self Administration; D012702:Serotonin Antagonists / Q000494:pharmacology*; D000077526:Tropisetron
D007211:Indoles; D012702:Serotonin Antagonists; D000431:Ethanol; D000077526:Tropisetron