Dr. Daniel Warren
Associate Professor - Ph.D., Brown University
Phone: (314) 977-2043
Fax: (314) 977-3658
Mail: Department of Biology, St. Louis University, 3507 Laclede Ave. St. Louis, MO 63103-2010
Courses:Human Cellular Physiology, Comparative Animal Physiology, Ecological Physiology, Comparative Biochemistry
My research program centers on understanding how animals are able to meet the physiological challenges imposed by their environments and by their natural and evolutionary histories. I use an integrative approach to understand why some animals, particularly pond turtles, are better able to tolerate dramatic changes in oxygen availability, temperature, and body fluid pH. My studies at the organismal level focus on acid-base regulation and carbohydrate metabolism, especially lactic acid, and those environmental and physiological factors that directly regulate these processes. My studies at the cellular level focus principally on the heart, which must and does continue to function under conditions (low oxygen and extremely low pH) that would otherwise be fatal to other vertebrates, including mammals. These include studies of cardiac pH regulation and the effects of pH on the cellular processes involved in excitation-contraction coupling, the sequence of events that starts with electrical depolarization of the cell and culminates in mechanical shortening. We aim to improve our understanding of how these processes evolved throughout evolution and to better characterize new or existing solutions to physiological problems that many kinds of organisms face. In addition, as global temperatures rise, it is imperative that we improve our understanding of the complex interaction between temperature and stresses like hypoxia and exercise in order to better predict how different organisms will cope with climate change. Our work may also lead to the identification of targets for therapeutic intervention to treat human diseases associated with in borne errors in metabolism and ischemia, a pathological condition that occurs most notably in heart and brain when blood flow (and, therefore, oxygen and glucose delivery) is restricted during myocardial infarction and stroke, respectively.
I am actively seeking graduate students at the level of M.S. and Ph.D. for study directed at several areas of my research. Please contact me directly for details.
Warren, D.E., Galli, G.L., Patrick, S.M. and Shiels, H.A. 2010. The cellular force-frequency response in ventricular myocytes from the varanid lizard, Varanus exanthematicus. Am. J. Physiol. Integr. Reg. Comp. 298: R567-74.
Galli, G.L., Warren, D.E. and Shiels, H.A. 2009. Ca2+ cycling in cardiomyocytes from a high-performance reptile, the varanid lizard (Varanus exanthematicus). Am. J. Physiol. Integr. Reg. Comp. 297: R1636-44.
Warren, D.E. and Jackson, D.C. 2008. Lactate metabolism in turtles: An integrative review. J. Comp. Physiol B. 178: 133-48.
Warren, D.E. and Jackson, D.C. 2007. Effects of temperature on anoxic submergence: skeletal buffering, lactate distribution and glycogen utilization in the turtle, Trachemys scripta. Am. J. Physiol. 293:R458-67.
Warren, D.E., Reese, S.A. and D.C. Jackson. 2006. Tissue glycogen and extracellular buffering limit the survival of red-eared slider turtles during anoxic submergence at 3°C. Physiol. Biochem. Zool. 79:736-744.
Warren, D.E. and D.C. Jackson. 2005. The role of mineralized tissue in the buffering of lactic acid during anoxia and exercise in the leopard frog, Rana pipiens. J. Exp. Biol. 208, 1117-1124.
Warren, D.E. and D.C. Jackson, 2004. Effects of swimming on metabolic recovery from anoxia in the painted turtle. J. Exp. Biol. 207, 2705-2713.