Florida State University Libraries Electronic Theses, Treatises and Dissertations The Graduate School 2009 Control of Prolactin Secretion by Central Oxytocin in Cervically Stimulated Ovariectomized Rats De'Nise T. McKee Follow this and additional works at the FSU Digital Library. For more information, please contact [email protected] FLORIDA STATE UNIVERSITY COLLEGE OF ARTS AND SCIENCES CONTROL OF PROLACTIN SECRETION BY CENTRAL OXYTOCIN IN CERVICALLY STIMULATED OVARIECTOMIZED RATS By DE’NISE T MCKEE A Dissertation submitted to the Department of Biological Science in partial fulfillment of the requirements for the degree of Doctor of Philosophy Degree Awarded: Summer Semester, 2009 The members of the committee approve the dissertation of De'Nise T McKee defended on July 9, 2009. __________________________________ Marc E Freeman Professor Directing Dissertation _____________________________________ Timothy M Logan Outside Committee Member __________________________________ Richard Bertram Committee Member __________________________________ Michael Meredith Committee Member __________________________________ J Michael Overton Committee Member Approved: ___________________________________________________________ P. Bryant Chase, Chair, Department of Biological Science The Graduate School has verified and approved the above-named committee members. ii ACKNOWLEDGEMENTS I would like to thank my professor, Marc E Freeman, for his generous support and supervision. He has provided an incredible environment for me to learn and grow scientifically and personally. I am very grateful to all of my current lab members: Richard Bertram, Ruth Cristancho, Cleyde Helena, Arturo Iglesias, Jessica Kennett, Joel Tabak, and Maurizio Tomaiuolo. I am appreciative for all their help and encouragement. I am also grateful to past lab members Marcel Egli, Mike Sellix Natalia Toporikova and Cheryl Fitch Pye for helping me transition into the lab and to Raphael Szawka for his generous assistance in the lab. A special thanks to Maristela Poletini for her unwavering dedication to my training. She has inspired me inside and outside of the lab and I am ultimately grateful for all of her guidance. Thank you to my committee members: Richard Bertram, Tim Logan, Michael Meredith and Michael Overton. They all have been incredibly supportive throughout this process. I am very thankful for the wonderful Neuroscience graduate students, an amazingly supportive group. I would like to acknowledge the technical support of Maurice Manning, Dano Fiore, and Wei Wu. I would like to acknowledge the NIH for financial support through a Minority Training grant, Minority Supplement and lab grants DK43200 and DA19356. I would also like to thank the Biology Department’s financial support through Teaching Assistantships and the support of the faculty and staff of the Neuroscience Program, Biology Department, and LAR. Finally, I would like to express my gratitude to family and friends for their vital love and encouragement. I thank my mom and dad (Brenda and Dennis), sisters (Chanda and Dia), brothers (Chaji and LaVonne), nieces, nephews, extended family, Chevonne, Lyndsey and Melita. I am very, very grateful for all of your support. iii TABLE OF CONTENTS LIST OF FIGURES ..........................................................................................................vi LIST OF TABLES .......................................................................................................... viii LIST OF ABBREVIATIONS .............................................................................................ix ABSTRACT .................................................................................................................... xii CHAPTER 1 INTRODUCTION TO PROLACTIN SECRETION ...................................... 1 Suckling Stimulus ........................................................................................................ 1 Estradiol Stimulus ........................................................................................................ 1 Mating Stimulus ........................................................................................................... 2 Pseudopregnancy. ................................................................................................... 3 Termination of mating-induced prolactin surges. ..................................................... 5 Evidence for a mating-induced mnemonic. .............................................................. 6 Control of Prolactin Secretion ...................................................................................... 7 Prolactin inhibiting factors. ....................................................................................... 7 Prolactin releasing factors. ..................................................................................... 10 CHAPTER 2 OXTYOCIN ACTION AT THE LACTOTROPH IS REQUIRED FOR PROLACTIN SURGES IN CERVICALLY STIMULATED OVARIECTOMIZED RATS ... 15 Materials and Methods .............................................................................................. 17 Experimental Design ................................................................................................. 23 iv Results ....................................................................................................................... 24 Discussion ................................................................................................................. 32 CHAPTER 3 NORADRENERGIC PROJECTIONS TO THE HYPOTHALAMIC PARAVENTRICULAR NUCLEUS ARE ACTIVATED BY CERVICAL STIMULATION IN OVARIECTOMIZED RATS ........................................................................................... 37 Materials and Methods .............................................................................................. 39 Experimental design .................................................................................................. 44 Results ....................................................................................................................... 44 Discussion ................................................................................................................. 48 CHAPTER 4 ACUTE ACTIVATION OF PARAVENTRICULAR OXYTOCIN NEURONS IN CERVICALLY STIMULATED OVARIECTOMIZED RATS ........................................ 53 Materials and Methods .............................................................................................. 54 Results ....................................................................................................................... 59 Discussion ................................................................................................................. 61 CHAPTER 5 DISCUSSION ........................................................................................... 64 Future Directions ....................................................................................................... 70 Appendix A: Copyright Permission Letters ................................................................... 72 Appendix B: IACUC Approval Letter ............................................................................ 75 REFERENCES .............................................................................................................. 77 BIOGRAPHICAL SKETCH ............................................................................................ 97 v LIST OF FIGURES Figure 1. Prolactin secretion in response to reproductive stimuli: .................................. 4 Figure 2. Illustration of neuroendocrine dopaminergic neurons. ..................................... 8 Figure 3. Activation of signal transduction pathway by prolactin. ................................... 9 Figure 4. Diagram of oxytocin neurons in the paraventricular nucleus ......................... 13 Figure 5. Connections within the network model. ......................................................... 25 Figure 6. Model simulation. .......................................................................................... 26 Figure 7. Prolactin secretion in rats with oxytocin antagonist infusion before cervical stimulation. .................................................................................................................... 29 Figure 8. Prolactin secretion in rats with oxytocin antagonist infusion after cervical stimulation. .................................................................................................................... 30 Figure 9. Prolactin secretion in cervically stimulated rats two days after cessation of OT antagonism. ................................................................................................................... 31 Figure 10. Dopamine activity in cervically stimulated rats with and without an oxytocin antagonist. ..................................................................................................................... 33 Figure 11. Representation of fluoro-gold injections. ..................................................... 45 Figure 12. Immunohistochemistry of brainstem noradrenergic neurons. ...................... 46 Figure 13. The percentage of brain stem noradrenergic neurons in cervically stimulated and non-cervically stimulated rats. ................................................................................ 47 vi Figure 14. Norepinephrine content in the paraventricular nucleus of rats with and without cervical stimulation. ..........................................................................................