title: Ethanol effects on multiple fixed-interval, fixed-ratio responding in mice with deletions of the serotonin transporter gene.
abstract: Serotonin transporter knockout (KO) mice self-administer less ethanol than either heterozygous or wild-type mice; however, the mechanistic basis for this difference remains unclear. Here we examine the possibility that ethanol more readily decreases responding in KO mice, thereby limiting ethanol self-administration. To examine whether KO mice were more sensitive to the response-decreasing effects of ethanol, we administered ethanol (0.2-3.2 g/kg) to mice responding under a multiple fixed-ratio 30-response, fixed-interval 300-s schedule of milk presentation. Ethanol decreased responding similarly in all three genotypes. Fixed-ratio responding tended to be decreased at lower doses than fixed-interval responding. The decreased level of ethanol self-administration in serotonin transporter KO mice is not explained by an increased sensitivity to the response-decreasing effects of ethanol in KO mice, as sensitivity to the response-decreasing effects of ethanol was similar in the KO, heterozygous, and wild-type mice.
authors.affiliation: Departments of aPsychiatry bPhysiology cPharmacology, University of Texas Health Science Center at San Antonio, San Antonio dDepartment of Behavioral Analysis, University of North Texas, Denton, Texas, USA.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Lamb
authors.forename: Jonathan W
authors.initials: JW
authors.lastname: Pinkston
authors.forename: Lynette C
authors.initials: LC
authors.lastname: Daws
mesh_terms: D000818:Animals; D002492:Central Nervous System Depressants / Q000494:pharmacology*; D003216:Conditioning, Operant / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D000431:Ethanol / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D012055:Reinforcement Schedule; D012646:Self Administration; D050486:Serotonin Plasma Membrane Transport Proteins / Q000172:deficiency* / Q000235:genetics
chemical_list: D002492:Central Nervous System Depressants; D050486:Serotonin Plasma Membrane Transport Proteins; D000431:Ethanol