City University of New York (CUNY) CUNY Academic Works All Dissertations, Theses, and Capstone Projects Dissertations, Theses, and Capstone Projects 2-2014 Intracellular Mechanisms Associated with Cocaine Induced Conditioned Place Preference Stephanie K. Nygard Graduate Center, City University of New York How does access to this work benefit ou?y Let us know! More information about this work at: https://academicworks.cuny.edu/gc_etds/84 Discover additional works at: https://academicworks.cuny.edu This work is made publicly available by the City University of New York (CUNY). Contact: [email protected] Intracellular Mechanisms Associated with Cocaine Induced Conditioned Place Preference by Stephanie K. Nygard A dissertation submitted to the Graduate Faculty in Psychology in partial fulfillment of the requirements for the degree of Doctor of Philosophy, The City University of New York 2014 ii © 2014 Stephanie K. Nygard All Rights Reserved iii This manuscript has been read and accepted by the Graduate Faculty in Psychology in satisfaction of the dissertation requirement for the degree of Doctor of Philosophy. Shirzad Jenab, Ph. D. ________________ _________________________ Date Chair of Examining Committee Maureen O’Connor ________________ _________________________ Date Executive Officer Vanya Quinones-Jenab, Ph. D. Victoria Luine, Ph. D. Jesus Angulo, Ph. D. Scott Russo, Ph. D. Supervisory Committee The City University of New York iv Abstract Intracellular Mechanisms Associated with Cocaine Induced Conditioned Place Preference by Stephanie K. Nygard Advisor: Professor Shirzad Jenab The aim of this dissertation was to investigate the intracellular responses associated with the acquisition and expression of cocaine-context associations. ERK (extracellular regulated kinase), CREB (cAMP responsive element binding protein), FosB and ΔFosB proteins were of particular interest due to their involvement in cocaine reward and in synaptic plasticity underlying learning and memory. We used the conditioned place preference (CPP) paradigm, which employs a Pavlovian conditioning procedure to establish an association between a drug-paired environment and the drug’s rewarding effects, to study the role of these signaling pathways in cocaine-context associations. N-methyl-D-aspartate receptor (NMDAR) antagonism prior to cocaine administration during conditioning blocked the acquisition of cocaine CPP and reduced Nucleus Accumbens (NAc) phosphorylated-ERK (pERK) levels following the CPP test (drug-free). NAc pERK levels increased after re-exposure to the cocaine-paired environment regardless of CPP expression. Conversely, Caudate Putamen (CPu) pERK and FosB protein levels only increased after CPP expression and re-exposure to the cocaine chamber. These results suggest that NAc ERK phosphorylation may be involved with retrieving the contextual information of a cocaine-association, without the expression of the behavior. Finally, we investigated whether ERK/CREB intracellular responses underlying cocaine environmental associations are sexually dimorphic. Following CPP expression, cocaine treated rats showed increased NAc pERK and pCREB and CPu ΔFosB levels. Cocaine females had a larger increase in CPu ΔFosB levels than cocaine males; partly due to lower protein levels in saline female rats when compared to saline males. CPP scores were positively correlated to NAc pERK and CPu FosB protein levels, suggesting that similar to males, the ERK/CREB intracellular pathway undergoes cocaine induced neuroplasticity in female rats. However, there seem to be intrinsic v sexual dimorphisms that may contribute to responses expressed after cocaine-CPP. Taken together, the different patterns of intracellular responses in the NAc and CPu likely indicate region specific roles for pERK/pCREB/FosB signaling in the acquisition and retrieval of cocaine-context associations. These results will aid in the advancement of general knowledge about the molecular formation and retrieval of cocaine-associated memories that can be used in the future when designing treatments for cocaine addiction that target both prevention and relapse. vi Acknowledgements I would like to thank my advisor Dr. Shirzad Jenab and co-advisor Dr. Vanya Quinones-Jenab for giving me the freedom to explore my own ideas while supporting me on my path to finishing my PhD. Thanks for putting up with me on some of the more difficult days and always encouraging me to keep going. I would also like to thank my committee member, Dr. Victoria Luine, for her intellectual and emotional support, tons of recommendation letters and for never losing confidence in me. Thanks to the rest of my committee, Dr. Scott Russo and Dr. Jesus Angulo for reading this dissertation, feedback and support. Thanks to the program secretary, Ellen Breheny, for her help and for always having whatever I need right at the top of the pile of papers on her desk. I don’t know how she does it! I would also like to thank some of my colleagues and friends. Thank you to the lab, Bailey Balouch, Miguel Briones, Anthony Klambatsen, Courtney Daly, Zane Ferguson and Mohamed Eltareb, for always keeping the lab entertaining. My friend and colleague Caroline Arout-Smith, I am so grateful to have had a friend to share this experience with. Thanks for keeping me sane by going crazy with me while writing our dissertations and postdoc searching and thanks for reading a draft of every e-mail I’ve sent in the last 6 months. Finally, my marvelous friends, Karen and James- my second parents, I wouldn’t have been able to finish this dissertation if it wasn’t for all of your help. Thanks for letting me live with you and taking care of me. I couldn’t ask for better friends and I am so lucky to have friends who know how to do life so well. WWKD? I also have to thank my amazing family because without their help (emotionally and financially), I would never have been able to complete this dissertation. Mom (Darth) and Dad, I am so lucky to have such caring and emotionally supportive parents. I know that I can always count on you for anything. Thanks for always being so proud of me! The pride I see in your eyes gives me the motivation to be my best and work harder every day. vii Table of Contents List of Tables ................................................................................................................................................. ix List of Figures ................................................................................................................................................ x Chapter 1: Introduction .................................................................................................................................. 1 I. Background ............................................................................................................................................ 1 A. Drug Addiction Theory ................................................................................................................. 1 B. Conditioned Place Preference (CPP) .......................................................................................... 4 C. Neural circuitry of addiction, learning and memory ..................................................................... 5 D. Cocaine: neural mechanisms ...................................................................................................... 9 II. Downstream cocaine-induced intracellular signaling .......................................................................... 16 A. ERK............................................................................................................................................ 16 B. CREB ......................................................................................................................................... 20 C. Sirtuins ....................................................................................................................................... 23 III. Cocaine-associated memories: Role of pERK/pCREB/ΔFosB .......................................................... 24 IV. Significance of work and working hypotheses ................................................................................... 29 V. Specific aims and hypotheses ............................................................................................................ 31 Chapter 2: Effects of NMDAR, SIRT1 and SIRT2 inhibition on the acquisition and expression cocaine- CPP ............................................................................................................................................................. 33 I. Introduction ......................................................................................................................................... 33 II. Methods............................................................................................................................................... 34 III. Results ............................................................................................................................................... 38 IV. Discussion ......................................................................................................................................... 58 Chapter 3: Differential intracellular signaling in the Nucleus Accumbens and Caudate Putamen during retrieval of a cocaine context association ................................................................................................... 60 I. Introduction ........................................................................................................................................