HSC

The research goal of the department is to establish the Physiology Research Program of the Graduate School of Biomedical Sciences of the University of North Texas Health Science Center at Fort Worth as an nationally and internationally recognized program of research and pre-doctoral and post-doctoral training.

The core of the department's research is the physiology and pathophysiology of the cardiovascular system. Members of the department are nationally and internationally recognized in their specific areas of research. Faculty members of the Department of Integrative Physiology serve on grant review panels for the National Institutes of Health and the American Heart Association, as well as the editorial boards of prestigious cardiovascular journals, and hold offices in several scientific and clinical organizations.

Current Research Projects

Steve W. Mifflin, Ph.D., Chair and Professor (Ph.D., Physiology and Biophysics, University of Texas Medical Branch, 1983). Research focuses on brainstem neurons that regulate blood pressure and respiration. Of particular interest is how these neurons adapt following chronic changes in physiological state (high blood pressure, low oxygen levels, sleep apnea, high salt intake). Studies are conducted over the spectrum from conscious, freely moving animals to single cell electrophysiology. The goal is to better understand if alterations in central nervous system function in pathophysiological states are protective or contribute to the pathophysiology. This knowledge can guide new therapeutic approaches.

James L. Caffrey, Ph.D., Professor (Ph.D., Physiology, University of Virginia, 1973). Laboratory studies the neuroendocrine regulation of the heart and circulation with specific emphasis on interactions between the autonomic neurotransmitters (acetylcholine and norepinephrine) and the endogenous opioids (endorphins, enkephalins, and dynorphins). Studies in this program include both molecular and intact organ system approaches in both human subjects and experimental animals. The laboratory emphasis includes the role of opioids in cardioprotection, cardiometabolic disease in general and diabetes in particular. A current laboratory focus is the identification of early markers of cardiometabolic disease in ethnic minorities and the development of strategic interventions to address those disparities. Our results suggest that determining the cardiac and neurovascular influences of endogenous opioids will help to develop new strategies for the treatment and prevention of the emerging world-wide epidemic of cardiometabolic disease.

J. Thomas Cunningham, Ph.D., Professor and Director of Cardiovascular Research Institute (Ph.D., Biopsychology, University of Iowa, 1988). We investigate the role of the central nervous system in body fluid homeostasis and cardiovascular regulation. Current projects focus on the physiological regulation of vasopressin release by visceral afferents and the roles of hypothalamic TRP channels and brain derived neurotrophic factors in syndrome of inappropriate ADH (SIADH). We also study hypothalamic mechanisms that influence sympathetic outflow in animal models of hypertension.

H. Fred Downey, Ph.D., Regents Professor and Vice Chair, (Ph.D., Biophysics, University of Illinois, 1968). Research delineates mechanisms to protect the heart from ischemia. Investigations focus on mechanisms controlling the coronary circulation and myocardial metabolism and on interactions between the coronary circulation and cardiac function. Current emphasis is on right ventricular physiology and on effects of osteopathic manipulation on lymph flow and immune function.

Patricia A. Gwirtz, Ph.D., Professor, (Ph.D., Physiology, Thomas Jefferson University, 1978). Informed consent applies the core principle of “Respect of Persons” to ethical research. Respect of research subjects implies considering and valuing the opinions and choices made by a subject having adequate knowledge. This requires that the subject fully comprehend the informed consent; otherwise their rights are compromised. A major barrier to comprehension occurs when the informed consent must be translated. Current research is examining the effects of these linguistic problems and other factors (e.g., education) on comprehension of the consent process.

Rong Ma, Ph.D. , Assistant Professor (Ph.D., Physiology, University of Nebraska, 1999) Research focuses on Ca2+-conductive channels (TRP channels) in kidney (glomerular mesangial cells and podocytes) and vascular smooth muscle cells. Major interests include regulation of TRP channels by protein kinases and reactive oxygen species, physiological relevance of TRP channels in kidney and blood vessels, and the association of TRP channel dysfunction with kidney and vascular diseases, such as diabetic nephropathy and vasculopathy

Robert T. Mallet, Ph.D., Professor (Ph.D., Physiology, George Washington University, 1986). Research emphasizes development of novel strategies to protect heart and brain from ischemic and inflammatory injury by modifying metabolic fuel supply to these organs, or by hypoxia conditioning. Current studies are defining mechanisms responsible for protection of the heart and brain by pyruvate during cardiac arrest-resuscitation, cardiopulmonary bypass surgery and hemorrhagic shock, and robust preservation of ischemic heart muscle and brain by intermittent, normobaric hypoxia conditioning.

Peter B. Raven, Ph.D., Professor (Ph.D., Scientific Basis of Physical Education, University of Oregon, 1969). Investigates cardiovascular regulation of the human during exercise and orthostasis. By using invasive and non-invasive procedures, integrative physiological mechanisms of cardiovascular regulation of the human are investigated during dynamic exercise and gravitational stress in both young and elderly individuals with varying levels of aerobic fitness.

Caroline Rickards, Ph.D., Assistant Professor (Ph.D., Doctor of Physiology, RMIT University Melbourne, Australia.  General research research interests encompass understanding the integrated cardiovascular, autonomic and cerebrovascular responses to hypovolemic stressors in humans, with an emphasis on hemorrhage and orthostasis.  While working with the US Army at the Institute for Surgical Research in San Antonio, my research focused on the early detection of hemorrhagic injury in trauma patients, and characterizing physiological differences between individuals with high versus low tolerance to this stress.  My current projects in the Department of Integrative Physiology continue this line of investigation, with a particular focus on examining the role of hemodyamic variability (i.e., in arterial pressure and cerebral blood flow) on the protection of cerebral tissue perfusion and oxygenation.  It is anticipated that these studies will have potential clinical applications to stroke, traumatic brain injury, hemorrhage, migraine, and orthostatic intolerance.


Xiangrong Shi, Ph.D., Associate Professor (Ph.D., Environmental Physiology, Yale University, 1989). Research interests include body fluid and blood pressure regulation under various environmental stresses; cardiovascular adaptations to acute physical activity and/or chronic exercise training; and the interrelation of blood volume and blood pressure control and regulatory mechanisms with aging.

Michael L. Smith, Ph.D., Professor (Ph.D., Biology, University of North Texas, 1986). Research efforts focus on the neural control of cardiovascular function relating to mechanisms of sudden cardiac death, syncope, exercise training effects, and mechanisms of the association between obstructive sleep apnea and hypertension.

Joseph P Yuan, Ph.D., Assistant Professor (Ph.D., Johns Hopkins School of Medicine, 2003).  Calcium (Ca2+) signaling mediates cardiac development and proliferation.  Aberrant Ca2+ signaling has been firmly linked to major diseases of the cardiovascular system; however, the molecular identities of the aberrant Ca2+ signaling have yet to be determined with certainty.  Abnormalities in store-operated Ca2+ channel (SOC) entry have been proposed to contribute to this aberrant Ca2 signaling.  SOC’s are Ca2+ channels that are activated in response to depletion of ER Ca2+ stores.  Thus, we are studying the molecular mechanism of gating of SOC’s toward better understanding the link between aberrant Ca2+ signaling and certain cardiovascular diseases.