Publications by authors named "James E Polston"

4 Publications

  • Page 1 of 1

Roux-en-Y gastric bypass increases intravenous ethanol self-administration in dietary obese rats.

PLoS One 2013 31;8(12):e83741. Epub 2013 Dec 31.

Department of Neural and Behavioral Sciences, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania, United States of America ; Department of Surgery, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania, United States of America.

Roux-en-Y gastric bypass surgery (RYGB) is an effective treatment for severe obesity. Clinical studies however have reported susceptibility to increased alcohol use after RYGB, and preclinical studies have shown increased alcohol intake in obese rats after RYGB. This could reflect a direct enhancement of alcohol's rewarding effects in the brain or an indirect effect due to increased alcohol absorption after RGYB. To rule out the contribution that changes in alcohol absorption have on its rewarding effects, here we assessed the effects of RYGB on intravenously (IV) administered ethanol (1%). For this purpose, high fat (60% kcal from fat) diet-induced obese male Sprague Dawley rats were tested ~2 months after RYGB or sham surgery (SHAM) using both fixed and progressive ratio schedules of reinforcement to evaluate if RGYB modified the reinforcing effects of IV ethanol. Compared to SHAM, RYGB rats made significantly more active spout responses to earn IV ethanol during the fixed ratio schedule, and achieved higher breakpoints during the progressive ratio schedule. Although additional studies are needed, our results provide preliminary evidence that RYGB increases the rewarding effects of alcohol independent of its effects on alcohol absorption.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0083741PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3877092PMC
September 2014

Alcohol reward is increased after Roux-en-Y gastric bypass in dietary obese rats with differential effects following ghrelin antagonism.

PLoS One 2012 7;7(11):e49121. Epub 2012 Nov 7.

Department of Neural and Behavioral Sciences, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania, United States of America.

Roux-en-Y gastric bypass (RYGB) is one of the most successful treatments for severe obesity and associated comorbidities. One potential adverse outcome, however, is increased risk for alcohol use. As such, we tested whether RYGB alters motivation to self-administer alcohol in outbred dietary obese rats, and investigated the involvement of the ghrelin system as a potential underlying mechanism. High fat (60%kcal from fat) diet-induced obese, non-diabetic male Sprague Dawley rats underwent RYGB (nā€Š=ā€Š9) or sham operation (Sham, nā€Š=ā€Š9) and were tested 4 months after surgery on a progressive ratio-10 (PR10) schedule of reinforcement operant task for 2, 4, and 8% ethanol. In addition, the effects of the ghrelin-1a-receptor antagonist D-[Lys3]-GHRP-6 (50, 100 nmol/kg, IP) were tested on PR10 responding for 4% ethanol. Compared to Sham, RYGB rats made significantly more active spout responses to earn reward, more consummatory licks on the ethanol spout, and achieved higher breakpoints. Pretreatment with a single peripheral injection of D-[Lys3]-GHRP-6 at either dose was ineffective in altering appetitive or consummatory responses to 4% ethanol in the Sham group. In contrast, RYGB rats demonstrated reduced operant performance to earn alcohol reward on the test day and reduced consummatory responses for two subsequent days following the drug. Sensitivity to threshold doses of D-[LYS3]-GHRP-6 suggests that an augmented ghrelin system may contribute to increased alcohol reward in RYGB. Further research is warranted to confirm applicability of these findings to humans and to explore ghrelin-receptor targets for treatment of alcohol-related disorders in RYGB patients.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0049121PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3492295PMC
May 2013

Lobeline augments and inhibits cocaine-induced hyperactivity in rats.

Life Sci 2006 Aug 17;79(10):981-90. Epub 2006 May 17.

Department of Psychological Sciences and Interdisciplinary Neuroscience Program, University of Missouri, Columbia, MO 65211, USA.

Lobeline has high affinity for nicotinic receptors and alters presynaptic dopamine storage and release in brain. Moreover, lobeline decreases the reinforcing and locomotor-activating properties of methamphetamine, suggesting that lobeline may be a pharmacotherapy for psychostimulant abuse. This study determined if lobeline alters cocaine-induced hyperactivity and if lobeline alters the induction and/or expression of sensitization to cocaine. On Days 1-12, male rats were administered lobeline (0.3 or 1.0 mg/kg) or saline, placed in an automated activity monitor for 20 min, administered cocaine (10, 20 or 30 mg/kg) or saline and returned to the monitor for 60 min. On Day 13, the effect of lobeline on the induction and expression of sensitization to cocaine was determined. Lobeline did not alter the effect of cocaine after acute injection. However, 1.0 mg/kg lobeline attenuated cocaine (10 and 20 mg/kg)-induced hyperactivity after repeated administration and prevented the development of sensitization to these cocaine doses. Interestingly, 0.3 mg/kg lobeline augmented cocaine (10 mg/kg)-induced hyperactivity after repeated administration. Lobeline did not alter the effect of 30 mg/kg cocaine. The present results indicate a complex interaction of lobeline with cocaine and support other research indicating a role for nicotinic receptors in the development of sensitization to psychostimulants.
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http://dx.doi.org/10.1016/j.lfs.2006.05.006DOI Listing
August 2006

Interaction of lobeline and nicotinic receptor ligands with the discriminative stimulus properties of cocaine and amphetamine.

Drug Alcohol Depend 2006 Oct 24;84(3):211-22. Epub 2006 Feb 24.

Department of Psychological Sciences, Interdisciplinary Neuroscience Program, University of Missouri, Columbia, MO 65211, USA.

Lobeline has high affinity for nicotinic acetylcholine receptors and inhibits the function of vesicular and plasmalemmal monoamine transporters. Moreover, lobeline has been shown to alter the neurochemical and behavioral effects of psychostimulants. The present study determined the effect of lobeline and drugs selective for nicotinic receptors on the discriminative stimulus properties of low doses of cocaine (1.6 or 5.0 mg/kg) or d-amphetamine (0.3 mg/kg) in rats, using a standard two-lever drug discrimination procedure with food reinforcement. Nicotine substituted for both amphetamine and cocaine. The nicotinic receptor antagonists mecamylamine and hexamethonium did not substitute for or block the cocaine or amphetamine stimulus. In contrast, lobeline substituted for cocaine, but did not substitute for amphetamine. In antagonism tests, lobeline doses that did not substitute for cocaine decreased responding on the cocaine-paired levers. Surprisingly, lobeline did not alter the discriminative stimulus properties of amphetamine. This research further supports the supposition that nicotine, cocaine and amphetamine produce similar, but distinct subjective states. Furthermore, the present findings suggest that lobeline has a complex mechanism of action to disrupt the behavioral effects of drugs of abuse.
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http://dx.doi.org/10.1016/j.drugalcdep.2006.01.012DOI Listing
October 2006
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