Volitional consumption of ethanol by fawn-hooded rats: effects of alternative solutions and drug treatments.
Behavioral and neurochemical measures of brain 5-hydroxytryptamine (5-HT) function in the Fawn-Hooded rat are abnormal relative to outbred strains of rats. Fawn-Hooded rats freely drink large amounts of 10% ethanol in the presence of water and have been proposed to be an animal model for studies related to alcoholism. In this study, Fawn-Hooded rats were given solutions of ethanol increasing in concentration from 3% to 30% (w/v in tap water) over 10 days with tap water in a second drinking tube and a third tube left empty. The solutions of ethanol that produced maximal drinking with a preference (ml ethanol/ml total fluid) near 50% ranged from 5% to 13%, which became the fixed individual concentrations for each rat. After a 5-day baseline period the rats were offered a solution in the third drinking tube of either 0.5% aspartame or chocolate Ultra SlimFast (diluted with water 2:1). The chocolate drink, but not aspartame, significantly reduced the consumption of alcohol by 73%. For the drug experiments, the rats were given successive 4-day periods of: baseline drinking; drug or saline injections b.i.d.; and a posttreatment period. Neither ipsapirone, a 5-HT1a partial agonist, nor naltrexone injected inhibited the intakes of ethanol solutions. Treatment with 2.5 mg/kg of amperozide, a 5-HT2 antagonist, decreased the consumption of ethanol by 38%, but also caused a decrease in consumption of food. These results show a pattern of drinking of increasing concentrations of ethanol different than other strains of rats.(ABSTRACT TRUNCATED AT 250 WORDS)
McMillen
B A
BA
Department of Pharmacology, School of Medicine, East Carolina University, Greenville, NC 27858, USA.
Williams
H L
HL
D000428:Alcohol Drinking; D000818:Animals; D001218:Aspartame; D001628:Beverages; D002099:Cacao; D004305:Dose-Response Relationship, Drug; D004326:Drinking / Q000187:drug effects; D005518:Food Preferences; D008297:Male; D010879:Piperazines / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012702:Serotonin Antagonists / Q000494:pharmacology
D010879:Piperazines; D012702:Serotonin Antagonists; C049058:amperozide; D001218:Aspartame