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Corongiu S, Dessì C, Espa E, Pisanu A, Pinna A, Lecca D, Fenu S, Cadoni C. Influence of Age and Genetic Background on Ethanol Intake and Behavioral Response Following Ethanol Consumption and During Abstinence in a Model of Alcohol Abuse. Front Behav Neurosci 2022; 16:858940. [PMID: 35418842 PMCID: PMC8996132 DOI: 10.3389/fnbeh.2022.858940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 02/25/2022] [Indexed: 11/13/2022] Open
Abstract
Genetic background and age at first exposure have been identified as critical variables that contribute to individual vulnerability to drug addiction. Evidence shows that genetic factors may account for 40–70% of the variance in liability to addiction. Alcohol consumption by young people, especially in the form of binge-drinking, is becoming an alarming phenomenon predictive of future problems with drinking. Thus, the literature indicates the need to better understand the influence of age and genetic background on the development of alcohol dependence. To this aim, the inbred rat strains Lewis (LEW, addiction prone) and Fischer 344 (F344, addiction resistant) were used as a model of genetic vulnerability to addiction and compared with the outbred strain Sprague-Dawley (SD) in a two-bottle choice paradigm as a model of alcohol abuse. During a 9-week period, adolescent and adult male rats of the three strains were intermittently exposed to ethanol (20%) and water during three 24-h sessions/week. Adult and adolescent SD and LEW rats escalated their alcohol intake over time reaching at stable levels, while F344 rats did not escalate their intake, regardless of age at drinking onset. Among adolescents, only F344 rats consumed a higher total amount of ethanol than adults, although only SD and LEW rats escalated their intake. Adult LEW rats, albeit having a lower ethanol consumption as compared to SD rats but greater than F344, showed a more compulsive intake, consuming higher amounts of ethanol during the first hour of exposure, reaching a higher degree of ethanol preference when start drinking as adolescents. Behavioral analysis during the first hour of ethanol consumption revealed significant strain differences, among which noticeable the lack of sedative effect in the LEW strain, at variance with F344 and SD strains, and highest indices of withdrawal (most notable jumping) in LEW rats during the first hour of abstinence days. The present results underscore the importance of individual genetic background and early onset of alcohol use in the progression toward abuse and development of alcohol addiction.
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Affiliation(s)
- Silvia Corongiu
- Neuropsychopharmacology Section, Department of Biomedical Sciences, University of Cagliari, Cagliari, Italy
| | - Christian Dessì
- Department of Biomedical Sciences, Institute of Neuroscience, National Research Council of Italy, Cagliari, Italy
| | - Elena Espa
- Neuropsychopharmacology Section, Department of Biomedical Sciences, University of Cagliari, Cagliari, Italy
| | - Augusta Pisanu
- Department of Biomedical Sciences, Institute of Neuroscience, National Research Council of Italy, Cagliari, Italy
| | - Annalisa Pinna
- Department of Biomedical Sciences, Institute of Neuroscience, National Research Council of Italy, Cagliari, Italy
| | - Daniele Lecca
- Neuropsychopharmacology Section, Department of Biomedical Sciences, University of Cagliari, Cagliari, Italy
| | - Sandro Fenu
- Neuropsychopharmacology Section, Department of Biomedical Sciences, University of Cagliari, Cagliari, Italy
| | - Cristina Cadoni
- Department of Biomedical Sciences, Institute of Neuroscience, National Research Council of Italy, Cagliari, Italy
- *Correspondence: Cristina Cadoni, ,
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Varnon CA, Dinges CW, Black TE, Wells H, Abramson CI. Failure to Find Ethanol-Induced Conditioned Taste Aversion in Honey Bees (Apis mellifera L.). Alcohol Clin Exp Res 2018; 42:1260-1270. [PMID: 29687910 DOI: 10.1111/acer.13761] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 04/15/2018] [Indexed: 11/29/2022]
Abstract
BACKGROUND Conditioned taste aversion (CTA) learning is a highly specialized form of conditioning found across taxa that leads to avoidance of an initially neutral stimulus, such as taste or odor, that is associated with, but is not the cause of, a detrimental health condition. This study examines if honey bees (Apis mellifera L.) develop ethanol (EtOH)-induced CTA. METHODS Restrained bees were first administered a sucrose solution that was cinnamon scented, lavender scented, or unscented, and contained either 0, 2.5, 5, 10, or 20% EtOH. Then, 30 minutes later, we used a proboscis extension response (PER) conditioning procedure where the bees were taught to associate either cinnamon odor, lavender odor, or an air-puff with repeated sucrose feedings. For some bees, the odor of the previously consumed EtOH solution was the same as the odor associated with sucrose in the conditioning procedure. If bees are able to learn EtOH-induced CTA, they should show an immediate low level of response to odors previously associated with EtOH. RESULTS We found that bees did not develop CTA despite the substantial inhibitory and aversive effects EtOH has on behavior. Instead, bees receiving a conditioning odor that was previously associated with EtOH showed an immediate high level of response. While this demonstrates bees are capable of one-trial learning common to CTA experiments, this high level of response is the opposite of what would occur if the bees developed a CTA. Responding on subsequent trials also showed a general inhibitory effect of EtOH. Finally, we found that consumption of cinnamon extract reduced the effects of EtOH. CONCLUSIONS The honey bees' lack of learned avoidance to EtOH mirrors that seen in human alcoholism. These findings demonstrate the usefulness of honey bees as an insect model for EtOH consumption.
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Affiliation(s)
| | | | - Timothy E Black
- Department of Psychology, Oklahoma State University, Stillwater, Oklahoma
| | - Harrington Wells
- Department of Biological Science, University of Tulsa, Tulsa, Oklahoma
| | - Charles I Abramson
- Department of Psychology, Oklahoma State University, Stillwater, Oklahoma
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Anderson RI, Moorman DE, Becker HC. Contribution of Dynorphin and Orexin Neuropeptide Systems to the Motivational Effects of Alcohol. Handb Exp Pharmacol 2018. [PMID: 29526023 DOI: 10.1007/164_2018_100] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Understanding the neural systems that drive alcohol motivation and are disrupted in alcohol use disorders is of critical importance in developing novel treatments. The dynorphin and orexin/hypocretin neuropeptide systems are particularly relevant with respect to alcohol use and misuse. Both systems are strongly associated with alcohol-seeking behaviors, particularly in cases of high levels of alcohol use as seen in dependence. Furthermore, both systems also play a role in stress and anxiety, indicating that disruption of these systems may underlie long-term homeostatic dysregulation seen in alcohol use disorders. These systems are also closely interrelated with one another - dynorphin/kappa opioid receptors and orexin/hypocretin receptors are found in similar regions and hypocretin/orexin neurons also express dynorphin - suggesting that these two systems may work together in the regulation of alcohol seeking and may be mutually disrupted in alcohol use disorders. This chapter reviews studies demonstrating a role for each of these systems in motivated behavior, with a focus on their roles in regulating alcohol-seeking and self-administration behaviors. Consideration is also given to evidence indicating that these neuropeptide systems may be viable targets for the development of potential treatments for alcohol use disorders.
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Affiliation(s)
- Rachel I Anderson
- Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, USA.,Science and Technology Policy Fellowships, American Association for the Advancement of Science, Washington, DC, USA
| | - David E Moorman
- Department of Psychological and Brain Sciences, Neuroscience and Behavior Graduate Program, University of Massachusetts Amherst, Amherst, MA, USA
| | - Howard C Becker
- Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, USA. .,Charleston Alcohol Research Center, Medical University of South Carolina, Charleston, SC, USA. .,Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA. .,Department of Veterans Affairs, Ralph H. Johnson VA Medical Center, Charleston, SC, USA.
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Anderson RI, Becker HC. Role of the Dynorphin/Kappa Opioid Receptor System in the Motivational Effects of Ethanol. Alcohol Clin Exp Res 2017; 41:1402-1418. [PMID: 28425121 DOI: 10.1111/acer.13406] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Accepted: 04/13/2017] [Indexed: 12/20/2022]
Abstract
Evidence has demonstrated that dynorphin (DYN) and the kappa opioid receptor (KOR) system contribute to various psychiatric disorders, including anxiety, depression, and addiction. More recently, this endogenous opioid system has received increased attention as a potential therapeutic target for treating alcohol use disorders. In this review, we provide an overview and synthesis of preclinical studies examining the influence of alcohol (ethanol [EtOH]) exposure on DYN/KOR expression and function, as well as studies examining the effects of DYN/KOR manipulation on EtOH's rewarding and aversive properties. We then describe work that has characterized effects of KOR activation and blockade on EtOH self-administration and EtOH dependence/withdrawal-related behaviors. Finally, we address how the DYN/KOR system may contribute to stress-EtOH interactions. Despite an apparent role for the DYN/KOR system in motivational effects of EtOH, support comes from relatively few studies. Nevertheless, review of this literature reveals several common themes: (i) rodent strains genetically predisposed to consume more EtOH generally appear to have reduced DYN/KOR tone in brain reward circuitry; (ii) acute and chronic EtOH exposure typically up-regulate the DYN/KOR system; (iii) KOR antagonists reduce behavioral indices of negative affect associated with stress and chronic EtOH exposure/withdrawal; and (iv) KOR antagonists are effective in reducing EtOH consumption, but are often more efficacious under conditions that engender high levels of consumption, such as dependence or stress exposure. These results support the contention that the DYN/KOR system plays a significant role in contributing to dependence- and stress-induced elevation in EtOH consumption. Overall, more comprehensive analyses (on both behavioral and mechanistic levels) are needed to provide additional insight into how the DYN/KOR system is engaged and adapts to influence the motivation effects of EtOH. This information will be critical for the development of new pharmacological agents targeting KORs as promising novel therapeutics for alcohol use disorders and comorbid affective disorders.
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Affiliation(s)
- Rachel I Anderson
- Charleston Alcohol Research Center, Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, South Carolina
| | - Howard C Becker
- Charleston Alcohol Research Center, Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, South Carolina.,Department of Neuroscience , Medical University of South Carolina, Charleston, South Carolina.,RHJ Department of Veterans Affairs Medical Center , Charleston, South Carolina
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McCarty R. Cross-fostering: Elucidating the effects of gene×environment interactions on phenotypic development. Neurosci Biobehav Rev 2016; 73:219-254. [PMID: 28034661 DOI: 10.1016/j.neubiorev.2016.12.025] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 12/15/2016] [Accepted: 12/17/2016] [Indexed: 02/03/2023]
Abstract
Cross-fostering of litters from soon after birth until weaning is a valuable tool to study the ways in which gene×environment interactions program the development of neural, physiological and behavioral characteristics of mammalian species. In laboratory mice and rats, the primary focus of this review, cross-fostering of litters between mothers of different strains or treatment groups (intraspecific) or between mothers of different species (interspecific) has been conducted over the past 9 decades. Areas of particular interest have included maternal effects on emotionality, social preferences, responses to stressful stimulation, nutrition and growth, blood pressure regulation, and epigenetic effects on brain development and behavior. Results from these areas of research highlight the critical role of the postnatal maternal environment in programming the development of offspring phenotypic characteristics. In addition, experimental paradigms that have included cross-fostering have permitted investigators to tease apart prenatal versus postnatal effects of various treatments on offspring development and behavior.
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Affiliation(s)
- Richard McCarty
- Department of Psychology, Vanderbilt University, Nashville, TN 37240 USA.
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Acevedo MB, Pautassi RM, Spear NE, Spear LP. Age-dependent effects of stress on ethanol-induced motor activity in rats. Psychopharmacology (Berl) 2013; 230:389-98. [PMID: 23775530 PMCID: PMC3859917 DOI: 10.1007/s00213-013-3163-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2013] [Accepted: 05/27/2013] [Indexed: 01/28/2023]
Abstract
RATIONALE It is important to study age-related differences that may put adolescents at risk for alcohol-related problems. Adolescents seem less sensitive to the aversive effects of ethanol than adults. Less is known of appetitive effects of ethanol and stress modulation of these effects. OBJECTIVES This study aims to describe the effects of acute social or restraint stress on ethanol-precipitated locomotor activity (LMA), in adolescent and adult rats. Effects of activation of the kappa system on ethanol-induced LMA were also evaluated. METHODS Adolescent or adult rats were restrained for 90 min, exposed to social deprivation stress for 90 or 180 min or administered with the kappa agonist U62,066E before being given ethanol, and assessed for LMA. RESULTS Adolescents were significantly more sensitive to the stimulating, and less sensitive to the sedative, effects of ethanol than adults. Basal locomotion was significantly increased by social deprivation stress in adult, but not in adolescent, rats. U62,066E significantly reduced basal and ethanol-induced locomotion in the adolescents. Corticosterone and progesterone levels were significantly higher in adolescents than in adults. CONCLUSIONS Adolescents exhibit greater sensitivity to ethanol-induced LMA and reduced sensitivity to ethanol-induced motor sedation than adult rats. Ethanol's effects on motor activity were not affected by acute stress. Unlike adults, adolescents were insensitive to acute restraint and social deprivation stress but exhibited motor depression after activation of the endogenous kappa opioid receptor system.
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Affiliation(s)
- María Belén Acevedo
- Instituto de Investigación Médica M. y M. Ferreyra (CONICET-UNC), Córdoba, C.P 5016, Argentina
| | - Ricardo Marcos Pautassi
- Instituto de Investigación Médica M. y M. Ferreyra (CONICET-UNC), Córdoba, C.P 5016, Argentina,Facultad de Psicología, Universidad Nacional de Córdoba, Córdoba, C.P 5000, Argentina,Corresponding author: Instituto de Investigación Médica M. y M. Ferreyra (INIMEC – CONICET), Friuli 2434, Córdoba, C.P 5016, T.E. 54-351-4681465, FAX 54-351-4695163, Argentina;
| | - Norman E. Spear
- Center for Development and Behavioral Neuroscience, Binghamton University, Binghamton, NY 13902-6000, USA
| | - Linda P. Spear
- Center for Development and Behavioral Neuroscience, Binghamton University, Binghamton, NY 13902-6000, USA
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Anderson RI, Agoglia AE, Morales M, Varlinskaya EI, Spear LP. Stress, κ manipulations, and aversive effects of ethanol in adolescent and adult male rats. Neuroscience 2012; 249:214-22. [PMID: 23276674 DOI: 10.1016/j.neuroscience.2012.12.028] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 12/11/2012] [Accepted: 12/18/2012] [Indexed: 12/16/2022]
Abstract
Elevated ethanol use during adolescence, a potentially stressful developmental period, is accompanied by insensitivity to many aversive effects of ethanol relative to adults. Given evidence that supports a role for stress and the kappa opioid receptor (KOR) system in mediating aversive properties of ethanol and other drugs, the present study assessed the role of KOR antagonism by nor-binaltorphimine (nor-BNI) on ethanol-induced conditioned taste aversion (CTA) in stressed (exposed to repeated restraint) and non-stressed male rats (Experiment 1), with half of the rats pretreated with nor-BNI before stressor exposure. In Experiment 2, CTA induced by the kappa agonist U62,066 was also compared in stressed and non-stressed adolescents and adults. A highly palatable solution (chocolate Boost) was used as the conditioned stimulus (CS), thereby avoiding the need for water deprivation to motivate consumption of the CS during conditioning. No effects of stress on ethanol-induced CTA were found, with all doses eliciting aversions in adolescents and adults in both stress conditions. However, among stressed subjects, adults given nor-BNI before the repeated stressor displayed blunted ethanol aversion relative to adults given saline at that time. This effect of nor-BNI was not seen in adolescents, findings that support a differential role for the KOR involvement in ethanol CTA in stressed adolescents and adults. Results from Experiment 2 revealed that all doses of U62,066 elicited aversions in non-stressed animals of both ages that were attenuated in stressed animals, findings that support a modulatory role for stress in aversive effects of KOR activation. Collectively, these results suggest that although KOR sensitivity appears to be reduced in stressed subjects, this receptor system does not appear to contribute to age differences in ethanol-induced CTA under the present test circumstances.
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Affiliation(s)
- R I Anderson
- Center for Development and Behavioral Neuroscience, Department of Psychology, Binghamton University, 4400 Vestal Parkway East, Binghamton, NY 13902-6000, USA.
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8
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Conditioned taste aversion and drugs of abuse: History and interpretation. Neurosci Biobehav Rev 2012; 36:2193-205. [DOI: 10.1016/j.neubiorev.2012.08.004] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Revised: 08/03/2012] [Accepted: 08/09/2012] [Indexed: 12/16/2022]
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9
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Early role of the κ opioid receptor in ethanol-induced reinforcement. Physiol Behav 2012; 105:1231-41. [PMID: 22261437 DOI: 10.1016/j.physbeh.2012.01.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Revised: 12/26/2011] [Accepted: 01/03/2012] [Indexed: 11/23/2022]
Abstract
Effects of early ethanol exposure on later ethanol intake emphasize the importance of understanding the neurobiology of ethanol-induced reinforcement early in life. Infant rats exhibit ethanol-induced appetitive conditioning and ethanol-induced locomotor activation, which have been linked in theory and may have mechanisms in common. The appetitive effects of ethanol are significantly modulated by μ and δ opioid receptors, whereas μ but not δ receptors are involved in the motor stimulant effects of ethanol during early development. The involvement of the κ opioid receptor (KOR) system in the motivational effects of ethanol has been much less explored. The present study assessed, in preweanling (infant) rats, the modulatory role of the KOR system in several paradigms sensitive to ethanol-induced reinforcement. Kappa opioid activation and blockade were examined in second-order conditioned place preference with varied timing before conditioning and with varied ethanol doses. The role of KOR on ethanol-induced locomotion and ethanol-induced taste conditioning was also explored. The experiments were based on the assumption that ethanol concurrently induces appetitive and aversive effects and that the latter may be mediated by activation of kappa receptors. The main result was that blockade of kappa function facilitated the expression of appetitive ethanol reinforcement in terms of tactile and taste conditioning. The effects of kappa activation on ethanol conditioning seemed to be independent from ethanol's stimulant effects. Kappa opioid activation potentiated the motor depressing effects of ethanol but enhanced motor activity in control subjects. Overall, the results support the hypothesis that a reduced function of the KOR system in nondependent subjects should attenuate the aversive consequences of ethanol.
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Pautassi RM, Nizhnikov ME, Acevedo MB, Spear NE. Naloxone blocks ethanol-mediated appetitive conditioning and locomotor activation in adolescent rats. Behav Brain Res 2010; 216:262-9. [PMID: 20708642 DOI: 10.1016/j.bbr.2010.08.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2010] [Revised: 07/30/2010] [Accepted: 08/04/2010] [Indexed: 12/20/2022]
Abstract
Age-related differences in ethanol sensitivity could put adolescents at risk for developing alcohol-related problems. Little information exists, however, about adolescent sensitivity to ethanol's appetitive effects and the neurobiological mechanisms underlying ethanol reinforcement during this developmental stage. The present study assessed the role of the opioid system in adolescent rats in an appetitive second-order schedule of ethanol reinforcement and ethanol-induced locomotor stimulation. On postnatal day 32 (PD32), animals were pretreated with the general opioid antagonist naloxone (0.0, 0.75, 1.50, or 2.5 mg/kg) and then given pairings of ethanol (0.0 or 2.0 g/kg, intragastrically) with intraoral pulses of water (conditioned stimulus 1 [CS₁], first-order conditioning phase). CS₁ delivery occurred 30-45 min after ethanol administration when the effect of ethanol was assumed to be appetitive. On PD33, adolescents were exposed to CS₁ (second-order conditioning phase) while in a chamber featuring distinctive exteroceptive cues (CS₂). Preference for CS₂ was then tested. Adolescents given CS₁-ethanol pairings exhibited greater preference for CS₂ than controls, indicating ethanol-mediated reinforcement, but only when not pretreated with naloxone. Blood alcohol levels during conditioning were not altered by naloxone. Experiment 2 revealed that ethanol-induced locomotor activation soon after administration, and naloxone dose-dependently suppressed this stimulating effect. The present study indicates that adolescent rats are sensitive to ethanol's reinforcing and locomotor-stimulating effects. Both effects of ethanol appear to be mediated by endogenous opioid system activation.
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Affiliation(s)
- Ricardo Marcos Pautassi
- Instituto de Investigación Médica M. y M. Ferreyra (INIMEC-CONICET), Córdoba, C.P. 5000, Argentina.
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Abstract
This paper is the 31st consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2008 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); and immunological responses (Section 17).
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Affiliation(s)
- Richard J Bodnar
- Department of Psychology and Neuropsychology Doctoral Sub-Program, Queens College, City University of New York, 65-30 Kissena Blvd, Flushing, NY 11367, United States.
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Pautassi RM, Nizhnikov ME, Spear NE. Assessing appetitive, aversive, and negative ethanol-mediated reinforcement through an immature rat model. Neurosci Biobehav Rev 2009; 33:953-74. [PMID: 19428502 PMCID: PMC2693872 DOI: 10.1016/j.neubiorev.2009.03.008] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2008] [Revised: 03/13/2009] [Accepted: 03/13/2009] [Indexed: 11/25/2022]
Abstract
The motivational effects of drugs play a key role during the transition from casual use to abuse and dependence. Ethanol reinforcement has been successfully studied through Pavlovian and operant conditioning in adult rats and mice genetically selected for their ready acceptance of ethanol. Another model for studying ethanol reinforcement is the immature (preweanling) rat, which consumes ethanol and exhibits the capacity to process tactile, odor and taste cues and transfer information between different sensorial modalities. This review describes the motivational effects of ethanol in preweanling, heterogeneous non-selected rats. Preweanlings exhibit ethanol-mediated conditioned taste avoidance and conditioned place aversion. Ethanol's appetitive effects, however, are evident when using first- and second-order conditioning and operant procedures. Ethanol also devalues the motivational representation of aversive stimuli, suggesting early negative reinforcement. It seems that preweanlings are highly sensitive not only to the aversive motivational effects of ethanol but also to its positive and negative (anti-anxiety) reinforcement potential. The review underscores the advantages of using a developing rat to evaluate alcohol's motivational effects.
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Affiliation(s)
- Ricardo M Pautassi
- Center for Development and Behavioral Neuroscience, State University of New York at Binghamton, Binghamton, NY 13902-6000, USA.
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