Copyright by Ryan Gregory Will 2016 The Dissertation Committee for Ryan Gregory Will Certifies that this is the approved version of the following dissertation: The Role of the Preoptic Area in Response to Cocaine Committee: Juan M. Dominguez, Supervisor Michela Marinelli, Co-Supervisor Christine L. Duvauchelle Andrea C. Gore Theresa A. Jones Marie H. Monfils The Role of the Preoptic Area in Response to Cocaine by Ryan Gregory Will, B.S. Dissertation Presented to the Faculty of the Graduate School of The University of Texas at Austin in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy The University of Texas at Austin May 2016 Dedication My wife Megan, who, for the last five years has patiently listened me practice (multiple times) every presentation I gave, tolerated my demanding schedule and brought me food on the weekends while I was running behavior. My parents The rats Acknowledgements My academic adviser Juan Dominguez for his constant support and guidance throughout graduate school, and for vastly improving my ability to convey scientific data to a wider audience My co-adviser Micky Marinelli for making me a better surgeon and allowing me to conduct behavioral experiments I would not have otherwise had the opportunity to perform. My committee members for helpful suggestions and advice throughout my dissertation work. The undergraduate students, graduate students, post-doctoral researchers, and lab managers in the Dominguez lab (Tori Nutsch, Tomoko Hattori, Kritikka Krishnan, Jon Turner, Julia Martz, Helen Hong and Alex Fanning) as well as the Marinessing labs (Adam Gordon, Matt Pomrenze, Angelo Blasio, and Rajani Maiya) who helped me conduct these experiments and provided support throughout this process. Finally, I would like to acknowledge three of my peers who were instrumental in both the execution of these studies as well as my development as a scientist. Without the help of Kevin Lominac, Daniel Tobiansky, and Vorani Ramashandra I would not be where I am today. v The Role of the Preoptic Area in Response to Cocaine Ryan Gregory Will, Ph.D. The University of Texas at Austin, 2016 Supervisor: Juan M. Dominguez Co-Supervisor: Michela Marinelli The preoptic area of the hypothalamus is ideally suited to modulate the behavioral and neural response to drugs of abuse such as cocaine. The preoptic area is broken up into two major subregions the medial preoptic area (mPOA) and the lateral preoptic area (LPO), both of which send dense projections to mesolimbic dopamine system. Specifically, both project to the ventral tegmental area (VTA), a brain region implicated in drug-associated reward. Previous work has demonstrated the mPOA is involved in the behavioral and neural response to cocaine in female rats, however the mechanism through which the mPOA modulates response to cocaine is unclear. Whether or not the mPOA also plays a role in response to cocaine in male rats is still not clear. Furthermore the role of the adjacent LPO in response to cocaine is unexplored, despite its anatomical relationship to the VTA and involvement in intracranial self-stimulation. Here I demonstrate that estradiol acts in the mPOA of female rats to modulate response to cocaine. Specifically, microinjections of estradiol directly into the mPOA one day prior to cocaine administration increase cocaine-induced dopamine levels in the nucleus accumbens. The mPOA is also involved in the behavioral regulation of response to cocaine in male rats, as mPOA lesions enhanced cocaine-induced locomotion and reward. vi Finally, activation of the LPO, with pharmacology or chemogenetics, potentiates reinstatement of cocaine seeking, an animal model of drug relapse. Together these results demonstrate that the preoptic area as a whole is involved in the regulation of the neural and behavioral response to cocaine and shed light on underlying regulatory mechanisms. vii Table of Contents List of Figures ....................................................................................................... xii Chapter 1: General introduction...............................................................................1 1.1 Cocaine use and abuse in the United States ..............................................1 1.2 Animal models of cocaine use ..................................................................4 1.2.1 Cocaine-induced locomotion ........................................................4 1.2.2 Conditioned place preference and self-administration measures of cocaine reinforcement ...................................................................4 1.2.3 Reinstatement of cocaine seeking .................................................5 1.3 Cocaine pharmacology and mechanisms of action ...................................6 1.3.1 The role of the mesolimbic dopamine system in response to drugs of abuse and reward...........................................................................8 1.3.2 Dopamine signaling in the mesolimbic circuit ...........................10 1.3.3 Pharmacologically manipulation of the mesolimbic dopamine system affects cocaine responsive behaviors ..........................................11 1.4 The role of gonadal hormones in cocaine response ................................13 1.4.1 Clinical results ............................................................................13 1.4.2 Preclinical results ........................................................................14 1.4.3 Neural circuits involved in gonadal hormone dependent response to cocaine ........................................................................................18 1.4.4 Summary .....................................................................................20 1.5 The preoptic area of the hypothalamus: a potential modulator of response to cocaine .................................................................................................21 1.5.1 Circuitry of the preoptic area ......................................................21 1.5.2 The medial preoptic area regulates hormonally sensitive naturally rewarding behaviors in female rodents .......................................22 1.5.3 The medial preoptic area regulates homeostatic and physiological behaviors .....................................................................................24 1.5.4 The medial preoptic area regulates cocaine response in females25 1.5.5 The medial preoptic area in males: a potential role in cocaine reward .....................................................................................................26 viii 1.5.6 The lateral preoptic area: a potential role in cocaine reward ......27 1.5.7 Summary .....................................................................................28 Chapter 2: Estrogen in the medial preoptic area modulates cocaine-induced dopamine in the NAc. ....................................................................................................29 2.1 Abstract ...................................................................................................29 2.2 Introduction .............................................................................................29 2.3 General methods .....................................................................................32 2.3.1 Subjects .......................................................................................32 2.3.2 Stereotaxic surgery and ovariectomies .......................................33 2.3.3 Microdialysis and cocaine administration ..................................33 2.3.4 Microinjections ...........................................................................34 2.3.5 Tissue collection: microinjection and probe placement ..............35 2.3.6 High performance liquid chromatography with electrochemical detection ......................................................................................35 2.3.7 Experimental design....................................................................36 2.3.8 Statistics ......................................................................................38 2.4 Results .....................................................................................................39 2.5 Discussion ...............................................................................................45 Chapter 3: The medial preoptic area modulates the behavioral response to cocaine in male rats ........................................................................................................53 3.1 Abstract ...................................................................................................53 3.2 Introduction .............................................................................................53 3.3 Materials and methods ............................................................................56 3.3.1Subjects ........................................................................................56 3.3.2 Surgery ........................................................................................56 3.3.3 Behavioral apparatus ...................................................................58 3.3.3.1 Locomotion .....................................................................58 3.3.3.2 Conditioned place preference .........................................58 3.3.4 Behavioral procedure ..................................................................59 3.3.4.1 Locomotion .....................................................................59 3.3.4.2