Photo of Shaun Morrison, Ph.D.

Shaun Morrison Ph.D.

  • (503) 494-1560
    • Professor of Neurological Surgery School of Medicine

Specific circuits within the CNS are dedicated to the maintenance of homeostasis and an optimal cellular environment through regulation of autonomic function. Disease states such as fever, obesity, diabetes, hypertension, autonomic hyperreflexia and cardiac arrhythmia are associated with altered regulation of the sympathetic outflow to cardiovascular and non-cardiovascular tissues. The Morrison lab's research uses electrophysiological and anatomical approaches to understand the functional organization, rhythmicities, developmental influences and pharmacology of the CNS circuits that regulate the sympathetic outflows controlling variables critical for homeostasis such as body temperature, energy expenditure, blood glucose, blood pressure, cardiac output and plasma catecholamines.We are currently pursuing three main areas of investigation in the rapidly growing field of autonomic neuroscience. The first concerns the regulation of the sympathetic outflow to brown adipose tissue in the rat as a model system for gaining insight into the central circuits involved in regulating energy metabolism and body temperature. The results of these studies will be relevant to altered thermoregulation occurring during fever and to the increasing public health problem of obesity, which can be viewed as an imbalance between energy intake and metabolism. We are also studying the CNS regulation of catecholamine release from the adrenal medulla, an important component of a variety of stress responses including hypoglycemia, hemorrhage, and exercise. The third area of research involves the organization of the medullary pathways regulating sympathetic outflow to the cardiovascular system. These experiments have indicated a novel source of excitatory input to the neural circuits that generate sympathetic outflow, a result which will contribute to our understanding of the elevated blood pressure in models of hypertension such as the spontaneously hypertensive rat. By addressing basic questions in autonomic neuroscience, we seek to understand the altered regulation of sympathetic outputs characteristic of several disease states.

Education

  • Ph.D., University of Vermont, Burlington Vermont 1980

Publications

  • "Adrenal epinephrine secretion is not regulated by sympathoinhibitory neurons in the caudal ventrolateral medulla" Brain Research May 8 1999
  • "Hypothalamic regulation of body temperature"  January 2013
  • "Efferent projections of neuropeptide Y-expressing neurons of the dorsomedial hypothalamus in chronic hyperphagic models" Journal of Comparative Neurology June 1 2013
  • "Raphe neurons with sympathetic-related activity" American Journal of Physiology - Renal Fluid and Electrolyte Physiology March 1984
  • "Central efferent pathways mediating skin cooling-evoked sympathetic thermogenesis in brown adipose tissue" American Journal of Physiology - Renal Fluid and Electrolyte Physiology January 2007
  • "Electrophysiological evidence for the modular organization of the reticular formation" Brain Research April 28 1987
  • "Neurons of rostral ventrolateral medulla mediate somatic pressor reflex" American Journal of Physiology - Renal Fluid and Electrolyte Physiology  1989
  • "Systemic leptin produces a long-lasting increase in respiratory motor output in rats" Frontiers in Physiology  2013
  • "2010 Carl Ludwig distinguished lectureship of the APS neural control and autonomic regulation section" Journal of Applied Physiology May 2011
  • "Differentiation of two cardiovascular regions within caudal ventrolateral medulla" American Journal of Physiology - Renal Fluid and Electrolyte Physiology  1991
  • "Central neural pathways for thermoregulation" Frontiers in Bioscience - Landmark January 1 2011
  • "Central neural regulation of brown adipose tissue thermogenesis and energy expenditure" Cell Metabolism May 6 2014
  • "Raphe pallidus excites a unique class of sympathetic preganglionic neurons" American Journal of Physiology - Renal Fluid and Electrolyte Physiology  1993
  • "Respiratory modulation of sympathetic nerve activity" American Journal of Physiology - Renal Fluid and Electrolyte Physiology  1996
  • "Assessment of three techniques for measurement of multiunit neural activity in sympathetic nerves" Brain Research Bulletin  1984
  • "Raphe pallidus neurons mediate prostaglandin E2-evoked increases in brown adipose tissue thermogenesis" Neuroscience September 26 2003
  • "Axonal branching patterns and funicular trajectories of raphespinal sympathoinhibitory neurons" Journal of Neurophysiology  1985
  • "Rostral ventrolateral medulla" Brain Research October 18 1991
  • "Lesions of rostral ventrolateral medulla (RVLM) or A5 reduce the 2-deoxy-glucose (2-DG)-evoked elevations in plasma epinephrine and blood glucose" FASEB Journal  1997
  • "Serotonin potentiates sympathetic responses evoked by spinal NMDA" Journal of Physiology December 1 2006
  • "Classification of raphe neurons with cardiac-related activity" American Journal of Physiology - Renal Fluid and Electrolyte Physiology  1982
  • "Adrenergic neurons in the rostral ventrolateral medulla" Progress in Brain Research  1989
  • "Autonomic regulation of brown adipose tissue thermogenesis in health and disease" Frontiers in Neuroscience  2014
  • "Direct pyrogenic input from prostaglandin EP3 receptor-expressing preoptic neurons to the dorsomedial hypothalamus" European Journal of Neuroscience December 2005
  • "Entrainment pattern between sympathetic and phrenic nerve activities in the Sprague-Dawley rat" American Journal of Physiology - Renal Fluid and Electrolyte Physiology June 2004
  • "Differentiated hemodynamic changes controlled by splanchnic nerve" Autonomic Neuroscience: Basic and Clinical June 30 2006
  • "A thermosensory pathway mediating heat-defense responses" Proceedings of the National Academy of Sciences of the United States of America May 11 2010
  • "Brown adipose tissue thermogenesis contributes to fentanyl-evoked hyperthermia" American Journal of Physiology - Renal Fluid and Electrolyte Physiology March 2005
  • "Central control of thermogenesis in mammals" Experimental Physiology July 2008
  • "Rostral ventromedial periaqueductal gray" Brain Research March 10 2006

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