THE 5-HT4 RECEPTOR ANTAGONIST, GR113808, REDUCES ETHANOL INTAKE IN ALCOHOL-PREFERRING RATS

The present study evaluated the effect of the selective 5-HT4 receptor antagonist, GR113808, on ethanol intake in alcohol-preferring rats. R ats were offered 10% ethanol 2 h/day. In the first experiment, rats ha d food and water ad lib and 10% ethanol was offered from 1800 to 2000 h. In the second experiment, food was freely available, 10% ethanol wa s offered 2 h/day, from 1800 to 2000 h, and water was offered for 4 h, from 1800 to 2200 h. In both experiments GR113808 was subcutaneously injected at doses of 1, 3, or 10 mg/kg for 4 consecutive days, 5 min b efore access to ethanol. From the first day of administration, GR11380 8 significantly reduced the volitional ethanol intake in water sated r ats at the three doses tested. In water-deprived rats, it reduced etha nol intake at 3 and 10 mg/kg, without modifying total fluid and food i ntake. In both experiments the effect of GR113808 remained rather stab le during the 4 days of administration. The present findings, showing that the 5-HT4 receptor antagonist, GR113808, selectively reduces etha nol intake in alcohol-preferring rats, suggest that 5-HT, receptors ma y play a role in alcohol intake control.