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Functional Studies of Descending Sympathetic Pathways in the Spinal Cord Loyola University Chicago Loyola eCommons Dissertations Theses and Dissertations 1973 Functional Studies of Descending Sympathetic Pathways in the Spinal Cord Robert Dale Foreman Loyola University Chicago Follow this and additional works at: https://ecommons.luc.edu/luc_diss Recommended Citation Foreman, Robert Dale, "Functional Studies of Descending Sympathetic Pathways in the Spinal Cord" (1973). Dissertations. 1326. https://ecommons.luc.edu/luc_diss/1326 This Dissertation is brought to you for free and open access by the Theses and Dissertations at Loyola eCommons. It has been accepted for inclusion in Dissertations by an authorized administrator of Loyola eCommons. For more information, please contact [email protected]. This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License. Copyright © 1973 Robert Dale Foreman FUNCTIONAL STUDIES OF DESCENDING SYMPATHEI'IC PATHWAYS IN THE SPDIAL CORD by Robert Dale Foreman A Disaertation Submitted to the Faculty of the Graduate School of Loyola University in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy June 1973 ·L l , Univers:t·J ,_~_cdi,a1 Center [ 10rary - oyo1a · Dedicated to my parents-­ Dad and Mom Foreman ii :BIOGRAPHY Robert D. Foreman was born on April 27, 1946, at Orange City, Iowa. He was raised on a farm near Montevideo, Minnesota and attended a small country school during his elementary school years. After moving back to Orange City, Iowa, he attended Western Christian High School at Hull, Iowa. :Before his college career began, he worked one year as a con­ struction worker in Artesia, California and later as a truck driver for a paint company in Orange City, Iowa. He attended Northwestern College in Orange City for two years, then transferred to Central College in Pella, Iowa. He was awarded his :Bachelor of Arts degree from Central College in the summer of 1969. After graduation he married Charlotte Poppen, who also attended Central College. She taught fifth grade at Lind.op Elementary School in Broadview, throughout the four years of graduate school. Robert began his graduate studies in the summer of 1969 in the Department of Physiology at Stritch School of Medicine. He worked under the direction of Robert D. Wurster and was supported by a Research Training Grant of the National Institutes of General Medical Sciences, of the National Institutes of Health. iii ACKNOWLEDGEMENTS I would like to take this opportunity to express my apprecia­ tion to Dr. Robert D. Wurster for his guidance and direction throughout the pa.st four years. His ability for teaching and for challenging me to think creatively, ma.de this dissertation possible. Above all, his inspiration and example will guide my attitudes and future goals as a physiologist. I would also like to express appreciation to the faculty of the Department of Physiology for sharing their knowledge and offering their criticism in molding my graduate education, as well as research. The preparation of this dissertation would not have been possible without the help of my dear wife, Charlotte. She spent many long hours typing the dissertation and preparing many of the figures. She was also a great source of moral support and encouragement through­ out. the past four years. A word of thanks is expressed to my colleagues who shared these past four years of graduate school with me. A special word of appreciation is expressed to Dr. J. Andrew Armour, who inspired thought and shared his opinions about this dissertation and about life in general. iv PU:BLICATIONS 1. FOREMAN, R.D. and R.D. Wurster. Localization of descending sympathetic spinal pathways. The Physiologist 14: 143, 1971. 2. ·Norris, J.E., R.D. Wurster and R.D. FOREMAN. Responses of the right ventricle during stimulation of ventral roots. The Physiologist 14: 203, 1971. 3. FOREMAN, R.D. and R.D. Wurster. Electrophysiological character­ istics of descending sympathetic spinal pathways. The Physiologist 15: 137, 1972. 4. FOREMAN, R.D. and R.D. Wurster. The influence of afferent stim­ ulation on descending sympathetic pathways of the spinal cord. Fed. Proc. 32: 1016, 1973. 5. FOREMAN, R.D. and R.D. Wurster. Localization and functional characteristics of descending sympathetic spinal pathways. Amer. J. Physiol., In Press, 1973. 6. Norris, J.E., R.D. FOREMAN, and R.D. Wurster. Inotropic and chronotropic responses of the canine heart during stimulation of the first five ventral thoracic roots. Circ. Res., Submitted, 1973. v TABLE OF CONTENTS Chapter Page I. INTRODUCTION •••••••••••••••••••••••••••••••••••••••••• 1 II. LITERATURE REVIEW••••••••••••••••••••••••••••••••••••• 4 A. Brain Stem Controlling the Cardiovascular System••••••••••••••••••••••••••••••••••••••••• 4 1. Medulla••••••••••••••••••••••••••••••••• 4 2. Hypothalamus •••••••••.•••••••••••••••••• 11 :B. Pathways Transmitting Cardiovascular ActivitY••••••••••••••••••••••••••••••••••••••• 15 c. Reflex Activation of the Cardiovascular ·System.......................................... 19 1. Somato-sympathetic Reflexes............. 19 2. Baroceptor Reflexes From the Carotid Sinus••••••••••••••••••••••••••••••••••• 26 III. METHODS AND MATERIALS••••••••••••••••••••••••••••••••• 30 A. Animal Preparation••••••••••••••••••••••••••••• 30 B. Lateral Spinal Cord Stimulations ••••••••••••••• 31 c. Reflex and Tonic Experiments ••••••••••••••••••• 33 n. Electrophysiology of the Descending Pathway •••• 35 IV. RESULTS••••••••••••••••••••••••••••••••••••••••••••••• 44 A. Lateral Spinal Cord Stimulation•••••••••••••••• 44 B. Bilateral Carotid Occlusions ••••••••••••••••••• 53 c. Electrophysiological Characteristics ••••••••••• 65 v. DISCUSSION •••••••••••••••••••••••••••••••••••••••••••• 82 VI. CONCLUSIONS ••••••••••.•••••••••••••••••••••••••••••••• • 106 Bll3LIOGRAPHY.................................................... 109 vi LIST OF TABLES Tables P88'! I. LATERAL SPINAL CORD STil1ULATIONS...................... 49 vii LIST OF FIGURES Figure Page 1. DIAGRAM OF INSTRUMENTS••••••••••••••••••••••••••••••••• 38 2. CALIBRATION GRAPH FOR DETER?1INING CONDUCTION TIME •••••• 39 3. CALIBRATION GRAPHS FOR DETERMINING AMPLITUDES OF EVOKED RESPONSES••••••••••••••••••••••••••••••••••••••• 42 4. CO:NTROL TRACINGS OF RANDOM NOISE AND SPONTANEOUS ACTIVITY••••••••••••••••••••••••••••·•••••••••••••••••• 43 STIMULATION OF THE DORSOLATERAL FUUICULUS •••••••••••••• 45 6. BLOOD PRESSURE RESPONSES FROM STIMULATION OF T1 DORSOLATERAL FUNICULUS••••••••••••••••••••••••••••••••• 47 7. ALTERATION IN BLOOD PRESSURE FROM STilIDLATION OF T2 AND T) DORSOLATERAL FUNICULI........................ 48 8. STI}'ITJLATION OF THE DORSOLATERAL FUNICULUS AFTER UNILATERAL AND BILATERAL LESIONS••••••••••••••••••••••• 52 9. BLOOD PRESSURE RESPONSES DURING BILATERAL CAROTID OCCLUSIONS............................................. 54 10. BLOOD PRESSURE TRACINGS DURING BILATERAL CAROTID OCCLUSIONS••••••••••••••••••••••••••••••••••••••••••••• 58 11. ALTERATIONS IN BLOOD PRESSURE DURING UNILATERAL CAROTID OCCLUSIONS..................................... 60 12. BILATERAL CAROTID OCCLUSIONS WITH SHAM PREPARATION ••••• 61 TRANSVERSE SECTION OF THE SPINAL CORD•••••••••••••••••• 63 viii LIST OF FIGURES Figure Page ALTERATIONS IN HEART RATE BEFORE AND AFTER SPINAL CORD LESIONS........................................... 64 c2 DORSOLATERAL FUNICULUS STI}IULATION •••••••••••••••••• 66 16. T2 DORSOLATERAL FUNICULUS STD1ULATION •••••••••••••••••• 68 STIMULATION CAUDAL AND ROSTRAL TO CS DORSOLATERAL FUNICULUS LESION••••••••••••••••••••••••••••••••••••••• 70 18. IPSILATERAL T8 STIMULATION OF DORSOLATERAL FUNICULUS •••••••••••••••••••••••••••••••••••••••••••••• 71 IPSILATERAL AND CONTRALATERAL c2 STil1ULATION 2 MM VENTROLATERAL TO THE DLS•••••••••••••••••••••••••• 73 20. IPSILATERAL T2 STHIULATION OF THE DLS BEFORE AND AFTER LESION••••••••••••••••••••••••••••••••••••••••••• 75 21. CONTRALATERALT STIMULATION OF THE DLS BEFORE AND AFTER LEsron ••••••••••••••••••••••••••••••••••••••• 11 22. IPSILATERAL c8 STIMULATION BEFORE AND AFTER LESION ••••• 7S CONTRALATERAL c8 STIJ>IDLATION BEFORE AND AFTER LESION ••• 80 24. IPSILATERAL TS DLS STUIULATION BEFORE AND AFTER LESION •••••••••••••••••••••• e •••••••••••••••••••••••••• 82 ix CHAPTER I INTRODUCTION Anatomical descriptions of the autonomic nervous system in the spinal cord have been based on the classical studies of Gaskell (50, 51) and Langley (91). They noted that the sympathetic component of the autonomic nervous system is located between the first thoracic and first or second lumbar segments, forming thoracolumbar outflow. Gaskell divided the sympathetic nervous system into three major com­ ponents. The first component is the afferent nerve which enters the dorsolateral sulcus and terminates on the preganglionic neuron which is the second component of the sympathetic reflexes. The preganglionic neuron was described as being analagous to the interneuron of the somatic reflex. The third component of the reflex was the postga.ng­ lionic neuron which originated in the paravertebral sympathetic trunk or prevertebral ganglia and terminated on the effector organs. The brain stem (66) and cortex(6o) have been analyzed to de­ termine how the supraspinal central nervous system controls the peripheral sympathetic nervous system. From a study of these two divisions of the sympathetic nervous system, it became apparent that the connections between the supraspinal central nervous system and 1 2 the preganglionic neurons have not been extensively examined.. This observation provided the
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