title: Effects of contingent and noncontingent nicotine on lever pressing for liquids and consumption in water-deprived rats.
abstract: Nicotine has been proposed to be a primary reinforcer and a reinforcement enhancer. To date, no studies have examined whether nicotine enhances consummatory behaviors or only operant responding (appetitive behaviors). Experiments were designed to test whether contingent and noncontingent nicotine enhance lever pressing for and consumption of fluids in water-deprived rats. Animals were water-deprived throughout all experiments. They were trained to press two levers under a variable interval (VI-20, 1-35s). Their lever pressing and water consumption were measured after noncontingent subcutaneous (s.c.) injection of nicotine (1mg/kg), and in 3 choice conditions (water and quinine solution (18µg/ml); water and nicotine (32µg/ml) solution; quinine (18µg/ml) and nicotine (32µg/ml) solutions) where nicotine was thus delivered contingently upon lever pressing. The effects of nicotine (1mg/kg; s.c.) on the consumption of water in a time-limited free access (1h) paradigm were assessed. Nicotine significantly increased lever pressing and the number of earned reinforcements on both levers in the two choice conditions and when administered s.c. compared to all groups that did not receive nicotine. However, under no condition did animals consume more fluids than baseline. Under the time-limited free access condition nicotine reduced water consumption. Although our findings do not support a reinforcing effect for nicotine, they are consistent with the incentive-amplification hypothesis. Its relevance for human smoking is yet unclear.
authors.affiliation: The School of Psychological Sciences, Tel Aviv University, Ramat Aviv, Israel. Electronic address: frenk@mta.ac.il.
authors.forename: Hanan
authors.initials: H
authors.lastname: Frenk
authors.affiliation: Department of Psychology, Center for Studies in Behavioural Neurobiology/Groupe de Recherche en Neurobiologie Comportementale, Concordia University, Montreal, Canada.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Martin
authors.affiliation: Department of Psychology, Center for Studies in Behavioural Neurobiology/Groupe de Recherche en Neurobiologie Comportementale, Concordia University, Montreal, Canada.
authors.forename: Cristina
authors.initials: C
authors.lastname: Vitouchanskaia
authors.affiliation: The School of Psychological Sciences, Tel Aviv University, Ramat Aviv, Israel.
authors.forename: Reuven
authors.initials: R
authors.lastname: Dar
authors.affiliation: Department of Psychology, Center for Studies in Behavioural Neurobiology/Groupe de Recherche en Neurobiologie Comportementale, Concordia University, Montreal, Canada.
authors.forename: Uri
authors.initials: U
authors.lastname: Shalev
mesh_terms: D000818:Animals; D002755:Choice Behavior / Q000187:drug effects; D003216:Conditioning, Operant / Q000187:drug effects; D003259:Consummatory Behavior / Q000187:drug effects; D004326:Drinking / Q000187:drug effects*; D008297:Male; D009538:Nicotine / Q000494:pharmacology*; D051381:Rats; D012054:Reinforcement, Psychology; D013997:Time Factors; D014867:Water / Q000378:metabolism*; D014868:Water Deprivation
chemical_list: D014867:Water; D009538:Nicotine
keywords: Nicotine; Reinforcement; Self-administration; Water deprivation