Integrated cardiorespiratory physiology

点击翻译按钮获取中文摘要

I study the heart, an organ that powers the cardiorespiratory system. I aim to discover mechanisms and unifying concepts that explain how different cardiac designs assist animals to live at a high environmental temperature or with low (or no) O2. One theme of my research program will provide new insights into specialized ion channels in cardiac cell membranes that are key to allowing an animal’s heartbeat to be automatic and rhythmic. We will investigate how the heartbeat is physiologically initiated and controlled when these channels open for ion movements. Also, a phylogenetic tree of the molecular structure of these ion channels will be created for hagfish (representatives of earliest chordates), cartilaginous fishes (at the base of the vertebrate lineage) and lungfish (at the base of the tetrapod lineage). A second theme builds on our physiological studies of rainbow trout populations that, through natural selection or hatchery practices, live at unusually high temperatures for this species. We will explore molecular mechanisms (changes to DNA and in RNA expression) that allow regular heartbeats at what would be normally a supra-optimal temperature for the species. By extension, we will see if Antarctic and Arctic fishes can express a new cardiac design and maintain physiological function after being warmed to temperatures realistic for global climate change. Hemoglobin-free icefish will be studied in Antarctica (an expedition funded by the USA’s National Science Foundation), while Arctic cod will be shipped to and acclimated in UBC’s new aquatic facility. Lastly, to enlighten how the first vertebrates may have developed a more secure O2 supply for their heart, we will complete our comprehensive phylogenetic and physiological exploration of the coronary circulation in cartilaginous fishes. Because all animals do not possess a coronary circulation and by studying representatives of basal vertebrates in which the coronary circulation first appeared, we will identify factors that likely drove the evolution of an O2 delivery system that better secures heart function when it must continue beating in extreme conditions. Thus, my research program will generate basic morphological, physiological and molecular information that help explain how cardiac structure and function ensure an adequate O2 supply for an animal. This information is of great significance to Canadians given the increased warming of our Arctic Ocean and the eutrophication our freshwater.