University of Kentucky UKnowledge Theses and Dissertations--Biology Biology 2016 MODULATORY ACTIONS OF SEROTONERGIC SYSTEM IN CARDIAC FUNCTION, BEHAVIOR, AND SENSORIMOTOR CIRCUIT ACTIVITY IN DROSOPHILA MELANOGASTER Zana R. Majeed University of Kentucky, [email protected] Digital Object Identifier: http://dx.doi.org/10.13023/ETD.2016.052 Right click to open a feedback form in a new tab to let us know how this document benefits ou.y Recommended Citation Majeed, Zana R., "MODULATORY ACTIONS OF SEROTONERGIC SYSTEM IN CARDIAC FUNCTION, BEHAVIOR, AND SENSORIMOTOR CIRCUIT ACTIVITY IN DROSOPHILA MELANOGASTER" (2016). Theses and Dissertations--Biology. 32. https://uknowledge.uky.edu/biology_etds/32 This Doctoral Dissertation is brought to you for free and open access by the Biology at UKnowledge. It has been accepted for inclusion in Theses and Dissertations--Biology by an authorized administrator of UKnowledge. For more information, please contact [email protected]. STUDENT AGREEMENT: I represent that my thesis or dissertation and abstract are my original work. Proper attribution has been given to all outside sources. I understand that I am solely responsible for obtaining any needed copyright permissions. I have obtained needed written permission statement(s) from the owner(s) of each third-party copyrighted matter to be included in my work, allowing electronic distribution (if such use is not permitted by the fair use doctrine) which will be submitted to UKnowledge as Additional File. I hereby grant to The University of Kentucky and its agents the irrevocable, non-exclusive, and royalty-free license to archive and make accessible my work in whole or in part in all forms of media, now or hereafter known. I agree that the document mentioned above may be made available immediately for worldwide access unless an embargo applies. I retain all other ownership rights to the copyright of my work. I also retain the right to use in future works (such as articles or books) all or part of my work. I understand that I am free to register the copyright to my work. REVIEW, APPROVAL AND ACCEPTANCE The document mentioned above has been reviewed and accepted by the student’s advisor, on behalf of the advisory committee, and by the Director of Graduate Studies (DGS), on behalf of the program; we verify that this is the final, approved version of the student’s thesis including all changes required by the advisory committee. The undersigned agree to abide by the statements above. Zana R. Majeed, Student Dr. Robin Lewis Cooper, Major Professor Dr. David Westneat, Director of Graduate Studies MODULATORY ACTIONS OF SEROTONERGIC SYSTEM IN CARDIAC FUNCTION, BEHAVIOR, AND SENSORIMOTOR CIRCUIT ACTIVITY IN DROSOPHILA MELANOGASTER DISSERTATION A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the College of Arts and Sciences at the University of Kentucky By Zana Rafiq Majeed Lexington, Kentucky Director: Dr. Robin Lewis Cooper, Associate Professor of Biology 2016 Copyright © Zana Rafiq Majeed 2016 ABSTRACT OF DISSERTATION MODULATORY ACTIONS OF SEROTONERGIC SYSTEM IN CARDIAC FUNCTION, BEHAVIOR, AND SENSORIMOTOR CIRCUIT ACTIVITY IN DROSOPHILA MELANOGASTER In this dissertation, I have focused on the role of serotonin (5-HT) as a modulator in heart rate, feeding and locomotion behaviors as well as sensorimotor circuit activity in Drosophila melanogaster. A general overview in the actions of the serotonergic (5-HTergic) system on the larval heart and nervous system in larvae and adults is reviewed in Chapter One. I sought to further study the actions of serotonergic system to provide additional insights into cellular and molecular underpinnings in the actions of 5-HT.In Chapter two, I present studies on mechanisms of action by 5-HT in larvae cardiac system. For this purpose, genetic and pharmacological approaches were used. The transgenic flies used expressed hM4Di receptors (designer receptors exclusively activated by designer drugs (DREADDs)) which were employed to manipulate the activity of Gαi heterotrimeric protein through activation of engineered G-protein coupled receptors hM4Di DREADD. The activation of hM4Di DREADD receptors by clozapine-N-oxide (CNO) arrested the heart beat; however, pharmacological manipulation of adenylyl cyclase activity and cAMP levels had no significant effect on heart rate. In Chapter Three the role of various 5-HT receptor subtypes that mediate 5-HT action in larval cardiac tissue is addressed. In this study, various 5-HT agonists and antagonists were employed. The pharmacological results demonstrate that a 5-HT2 agonist significantly increases the heart rate. Furthermore, 5-HT2 antagonist, markedly reduces the effect of 5-HT. In addition, I employed genetic approaches to corroborate the pharmacological results. In addition, I investigated the role of the 5-HTergic system in locomotion and feeding behaviors as well as in modulation of sensorimotor circuits. This study is delineated in Chapter Four. The 5-HT biosynthesis was dysregulated by feeding Drosophila larvae various pharmacological agents. 5-HT receptor subtypes were manipulated using RNA interference mediated knockdown and 5-HT receptor insertional mutations. Moreover, synaptic transmission at 5-HT neurons was blocked or induced in both larvae and adult flies. The results demonstrate that disruption of components within the 5-HT system significantly impairs locomotor activity and feeding behavior in larvae. In addition, acute activation of 5-HT neurons disrupts normal locomotor activity in adult flies. In Chapter Five, I addressed direct actions of fluoxetine on synaptic transmission at neuromuscular junctions (NMJs), neural properties, and cardiac function unrelated to fluoxetine’s action as a selective 5-HT reuptake inhibitor using Drosophila, crayfish and primary neurons in mouse model system. Fluoxetine application blocked action potentials in crayfish axons, enhanced occurrences of spontaneous synaptic vesicle fusion events at NMJs of both Drosophila and crayfish. In rodent primary neurons, fluoxetine application resulted in increase of cytoplasmic Ca2+. I also developed teaching modules, which are presented in Chapter Seven, to guide students how to exploit a vast array of genetic tools, such as optogenetics in Drosophila to manipulate various neural circuits and to observe their effects on behavior and sensorimotor circuit activity. I also developed a module to teach college level students a hands-on experiment regarding proprioception and tension receptors in crab limb, which is detailed in Chapter Eight. Keywords: serotonin, 5-HT receptors, heart rate, locomotion and feeding, sensorimotor circuit Zana Rafiq Majeed April 11, 2016 MODULATORY ACTIONS OF SEROTONERGIC SYSTEM IN CARDIAC FUNCTION, BEHAVIOR, AND SENSORIMOTOR CIRCUIT ACTIVITY IN DROSOPHILA MELANOGASTER By Zana Rafiq Majeed Dr. Robin Lewis Cooper Director of Dissertation Dr. David Westneat Director of Graduate Studies April 11, 2016 i ACKNOWLEDGEMENTS During the course of my study as a graduate student, I learned invaluable experiences in my field of specialty and it would not have been easy to achieve without the help and support of many people. I am very grateful to my advisor Dr . Robin L. Cooper who guided me to achieve my goals as a researcher. He was very generous to let me work in his lab and introduce me to the field of Neurobiology. With his encouragement and continuous support, I published many scientific papers in peer- reviewed journals. I also am thankful to my PhD committee members, Dr. Douglas A. Harrison, Dr. Bruce O’Hara, Dr. Olivier Thibault, for their constructive feedbacks and suggestions that improved my work. Coming to the United States of America to learn new biological techniques and carry out modern scientific research was a dream come true to me, which would have not been possible without assistance and financial support from my sponsor the Higher Committee for Education Development (HCED) in Iraq. My sincere appreciation is extended to Cooper lab members and the staff at the Department of Biology, University of Kentucky. I express my gratitude to undergraduate and high school students, Audra Stacy, Tripp Crosthwaite, Kristin Cornwell, Robin Soveland, Aubrey Bankemper, Esraa Abdeljaber, Felicitas Koch, Emily Greene, and Brianna Demers, who helped me in the lab. I thank all my family members, my parents and siblings, for their support and keeping my morale high. I am very grateful to my kind mother Shukria Ali Ibrahim who has supported me throughout my education. I extend my deepest gratitude to my generous father Rafiq Majeed Ahmed who has always been there for me to obtain a fine education. In addition, I thank my gracious and lovely wife Hedy Ahmed Chawsheen, a great friend and partner, for her patience and encouragement during the course of my study. ii TABLE OF CONTENTS List of Tables …………………………………………………………………………….....vi List of Figures ………………………………………………………...…………………….vii Chapter One: Introduction: An overview of neuromodulation actions in organisms….1 Neuromodulation in physiology and behavior……………………………………1 Drosophila melanogaster as a model system ………………………………......2 Drosophila melanogaster cardiovascular system…………………………….….3 Drosophila melanogaster nervous system……………………………….….…...4 Serotonergic system in Drosophila melanogaster………………………..…..…7 Sensorimotor circuit in Drosophila melanogaster larvae……………….………10 Serotonergic neurons wiring diagram within sensorimotor neural networks…………………………………………………………………...12