The Effects of Some Typical and Atypical Neuroleptics on Gene Regulation: Implications for the Treatment of Schizophrenia A Thesis Submitted to the College of Graduate Studies and Research in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in the Department of Psychiatry, University of Saskatchewan, Saskatoon, Canada BY Jennifer Chlan-Fourney Fa11 2000 O Copyright Jennifer Chlan-Fourney. All rights reserved. National Library BibliothMue nationale du Canada Acquisitions and Acquisitions et Bibliographic Services services bibliographiques 395 Wellington Street 395, rue Wellington Ottawa ON KIA ON4 OttawaON KlAON4 Canada Canada The author has granted a non- L'auteur a accorde une licence non exclusive licence allowing the excIusive pennettant a la National Library of Canada to Bibliotheque nationale du Canada de reproduce, loan, distribute or sell reproduire, prster, distribuer ou copies of this thesis in microform, vendre des copies de cette these sous paper or electronic formats. la fome de microfiche/film, de reproduction sur papier ou sur foxmat Bectronique . The author retains ownership of the L'auteur conserve la proprikte du copyright in this thesis. Neither the droit d'auteur qui protege cette these. thesis nor substantial extracts from it Ni la these ni des extraits substantiels may be printed or otherwise de celle-ci ne doivent Stre imprimes reproduced without the author's ou autrement reproduits sans son permission. autorisation. PERMISSION TO USE In presenting this thesis in partial fulfillment of the requirements for a Postgraduate degree from the University of Saskatchewan, I agree that the Libraries of this University may make it freely available for inspection. I further agree that permission for copying of this thesis in any manner, in whole or in part, for scholarly purposes may be granted by the professor or professors who supervised my thesis work or, in their absence, by the Head of the Department or the Dean of the College in which my thesis work was done. It is understood that any copying or publication or use of this thesis or parts thereof for financial gain shall not be allowed without my written permission. It is also understood that due recognition shall be given to me and to the University of Saskatchewan in any scholarly use which may be made of any material in my thesis. Requests for permission to copy or to make other use of material in this thesis in whole or part should be addressed to: Head, Department of Psychiatry, University of Saskatchewan Saskatoon, Saskatchewan (S7N 5E4) ABSTRACT The cellular mechanisms by which antipsychotic medications (neuroleptics) produce their therapeutic effects in schizophrenia are largely unknown. Although neuroleptic efficacy is attributed to central dopamine D2 andlor serotonin 5-HT2 receptor antagonism, clinical improvements in schizophrenia are not seen until two or three weeks after daily neuroleptic administration. The mechanisms underlying the neuroleptic response must therefore occur downstream from initial receptor blockade and be a consequence of continuous. chronic neurotransmitter receptor blockade. The goal of the present study was to use neuroleptics with varing dopamine vs. serotonergic receptor blocking profiles to elucidate some of these intracellular post receptor mechanisms. Since both the final steps of dopamine and serotonin synthesis require the enzyme aromatic L-amino acid decarboxylase (AADC), the effects of neuroleptics on AADC gene (mRNA) expression were examined in PC12 cells and compared to their effects on tyrosine hydroxylase (TH; the apparent rate limiting enzyme in the synthesis of dopamine) and c-fos (an early immediate gene [IEG] known to regulate tyrosine hydroxylase) gene expression. The neuroleptics examined did not significantly regulate AADC mRNA in PC12 cells, and only haloperidol regulated TH and c-fos mRNA. Later in vivo studies in rats showed that acute neuroleptic administration increased c-fos mRNA in a number of brain regions, whereas the immunoreactivity of a related IEG (delta FosB) was increased upon chronic treatment. These studies and a subsequent dose response study demonstrated that upregulation of both c-fos mRNA and delta FosB imrnunoreactivity was most prominent in dopaminergic projection areas, including the striatum and nucleus accumbens. Because it has been suggested that neuroleptic treatment might prevent neurodegeneration in schizophrenia, the effects of neuroleptics on the mRNA expression of neuroprotective target genes of delta FosB were examined both in vitro and in vivo. These genes included brain-derived neurotrophic factor (BDNF), the neuroprotective enzyme superoxide dismutase (SOD), and the low affinity nerve growth factor receptor (p75). While dopamine Dg blockade unfavorably regulated BDNF and p75 mRNA, 5-HT2 blockade either had no effect on or favorably regulated BDNF, SOD, and p75 mRNA. Thus, although very little about the contribution of serotonergic blockade to the neuroleptic response was determined in the present study, dopaminergic blockade was found to regulate IEGs and several of their target genes. Future studies will be needed to understand the role of 5-HT2 receptor blockade in the neuroleptic response. ACKNOWLEDGMENTS There are a number of people that I would like to thank who have supported me during my education and who have helped me complete my dissertation. Foremost, I must thank my mother and father for their outstanding kindness, patience, and support they have given me throughout my university studies and for the encouragement they gave me to complete my Ph.D degree. I would also like to thank my husband Daryl for tolerating the chaos I created in finishing my thesis, and the rest of my family, including my brother Malcolm, my grandparents, and my aunts, uncles, and cousins for a number of things - including all the errands they ran to help me further my education (Malcolm and Morgana), and for allowing me to bring homework to do on family vacations (everyone). A special thanks goes to my friends from Saskatoon for helping me keep my sanity, my friends from Texas who made me feel smart when I didn't feel that way, and my friends from home (Flin Flon) who didn't get angry when I said I didn't have time to write. Many people in our lab and in the department have been very helpful not only as friends, but also as research colleagues, especially Gabriel, Paula, and Jin. Many thanks to my supervisors Drs. X.-M. Li and A.V. Juorio, who guided me throughout my post-graduate endeavors and gave me the freedom to pursue the research that I had always wanted to do. Thanks are also extended to my advisory committee, Drs. B. Davis, S. Richardson, D. Malcolm, R. Bowen, A.J. Nazarali, A.A. Boulton, and to my external examiner, Dr. Glen Baker for their kind support and thoughtful guidance. I would also like to thank many other researchers that I have collaborated with and received guidance from, including Drs. J.A. Mills, B.E. Kosofsky, E.J. Nestler, I.A. Paterson, D. Schreyer. P. Gillies, and Xia Zhang. I would also like to thank the Schizophrenia Society of Saskatchewan, for their wonderful support throughout my program and for the opportunities I had to meet them and be involved with their society. My interactions with the society made my research much more enjoyable and meaningful to me than had I been isolated by myself in a laboratory. TABLE OF CONTENTS The Effects of Some Typical and Atypical Neuroleptics on Gene Regulation: Implications for the Treatment of Schizophrenia PERMISSION TO USE ...................................................................................... I .. ABSTRACT.. ..................................................................................................... .II ACKNOWLEDGEMENTS.................................................................................. iv TABLE OF CONTENTS .................................................................................... vi LIST OF TABLES ............................................................................................. xiv LIST OF FIGURES.......................................................................................... xiv LIST OF ABBREVIATIONS............................................................................ xvii 1. INTRODUCTION..................................................................................... 1 1.I Schizophrenia...................................................................................... 1 1.1.1 Definition and clinical presentation................................................. 1 1.1.2 Treatment and prognosis............................................................... 2 1.2 Selected theories of cause and aetiology in schizophrenia................... 3 1.2.1 Neurotransmitter and receptor theories ........................................... 3 1.2.1.1 Dopamine.................................................................................... 4 1.2.1 -2 Serotonin.................................................................................... 6 1.2.1 -3 Glutamate................................................................................... 7 1.2.2 Theories of neuropathology............................................................... 9 1.2.2.1 Neurodevetopmental theories ..................................................... 10 1.2.2.2 Neurodegeneration in schizophrenia .................................... 12 1.2.2.2.1 Symptoms of schizophrenia worsen over time ...................... 13 1.2.2.2.2