title: The selective serotonin reuptake inhibitor paroxetine decreases breakpoint of rats engaging in a progressive ratio licking task for sucrose and quinine solutions.
abstract: Increased serotonergic activity has been shown to reduce motivation to ingest, which may involve, in part, gustatory processes. Here, we examined the effect of paroxetine, a selective serotonin reuptake inhibitor, on appetitive responding for a preferred and an avoided taste solution using a progressive ratio (PR) task in which licking was employed as the operant. Male Sprague-Dawley rats (n = 8/taste stimulus) were trained to respond for a concentration series of sucrose or quinine on fixed and PR schedules of reinforcement. Performance for sucrose was assessed while the rats were partially food- and water-restricted and nondeprived, and performance for water and quinine was assessed while the rats were water-deprived. Then, the rats were injected with vehicle (10% dimethyl sulfoxide, 1mL/kg intraperitoneal [ip], -1h) or paroxetine (5mg/kg), and their responding on a PR schedule for sucrose measured when the rats were nondeprived or for water and quinine when the rats were water-deprived. Paroxetine decreased breakpoint, which was defined as the number of operant (e.g., dry) licks in the final reinforced ratio, for water, quinine, and sucrose. This demonstrates that a general systemic increase in serotonergic activity decreases the appetitive-based responses to both preferred and nonpreferred fluids under different deprivation states.
authors.affiliation: Department of Psychology, Florida State University, Tallahassee, FL 32306-4301, USA. cmathes@neuro.fsu.edu
authors.forename: Clare M
authors.initials: CM
authors.lastname: Mathes
authors.forename: Jillian R
authors.initials: JR
authors.lastname: Gregson
authors.forename: Alan C
authors.initials: AC
authors.lastname: Spector
mesh_terms: D000818:Animals; D001070:Appetitive Behavior / Q000187:drug effects*; D005508:Food Deprivation; D008297:Male; D017374:Paroxetine / Q000494:pharmacology*; D011803:Quinine / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012054:Reinforcement, Psychology; D017367:Selective Serotonin Reuptake Inhibitors / Q000494:pharmacology*; D013395:Sucrose / Q000494:pharmacology*; D014868:Water Deprivation
chemical_list: D017374:Paroxetine; D011803:Quinine; D017367:Selective Serotonin Reuptake Inhibitors; D013395:Sucrose